<?xml version="1.0"?>

<!--
	Remote Telescope Markup Language 2.0 XML DTD Version 0.2
	2001.07.24
	F.V. Hessman, Universitaets-Sternwarte Goettingen

	The included documentation should be enough to enable a fully
	functional dynamic web-based information service documenting all
	the detailed functionality.
-->

<!-- 
	RTML v2.1

	31/10/2001
	Jason Etherton

        Slight revisions and removal mistakes from rtml2.dtd 
	( single quoted strings, mismatched parentheses )

	Added ENTITY %rtmlDocumentModes = "score"

	Added ENTITY %statusTypes = "aborted"

        Defined ATTRIBUTE type = "(fixed|calculated)" to Exposure

	Defined ENTITY %exposureType = "(time|snr)"  

	Added ELEMENT Name as daughter of Location and Telescope

	Added ATTRIBUTE %timeUnits to ProperMotion ( RA = sec/yr )

	Defined ELEMENT Parallax

	Added ATTRIBUTE status = %statusTypes to Observation

	Removed Filter ATTLIST and replaced with defined daughter ELEMENTS:
	    FilterNumber   (#CDATA)
	    FilterProfile  (wavelength=CDATA width=CDATA units=%lengthUnits)
	    FilterType     (type=%filterTypes)

	Defined ELEMENT Reduction = (#CDATA, ObjectList?)

	Defined ELEMENT ObjectList = (#CDATA)
	Added ATTRIBUTE number (#CDATA) to ObjectList

	Defined ELEMENT MagnitudeFilter = (#CDATA)
	Added ATTRIBUTE minimum CDATA to MagnitudeFilter
	Added ATTRIBUTE maximum CDATA to MagnitudeFilter

	Define ELEMENT PositionFilter = (#CDATA, RightAscension+, Declination+)
	Added ATTRIBUTE radius CDATA to PositionFilter
	Added ATTRIBUTE units  %angleUnits to PositionFilter

	Defined ELEMENT Object = (#CDATA, RightAscension, Declination, Flux)

        Defined ELEMENT IntelligentAgent
	Defined ENTITY %objectListTypes
	Defined ENTITY %imageDataTypes
-->

<!-- XML Schema-style documentation
<annotation>
<documentation>
	<name>RTML - Remote Telescope Markup Language</name>
	<revision value="1.0">
		<author>Shawn Gorden</author>
		<date>1999.06.23</date>
		Initial formulation of RTML using DTD.
	</revision>

	 <revision value="1.0">
		<author>Jon Aymon</author>
		<date>2000.07.10</date>
		Tested for well-formedness on Windows98 Internet Explorer XML
		Tested for validity on Microsoft XMLINT.
	</revision>

	<revision value="2.0">
		<author>Frederic V. Hessman</author>
		<date>2001.05.30</date>
		Major revision preparing for XML Schema, lower-case names, 
		fewer attributes to improve commentability and ease of use.
	</revision>

	<revision value="2.0b">
		<author>Frederic V. Hessman</author>
		<date>2001.07.22</date>
		Major re-revision after a bit of criticism throwing out the 
		&lt;request&gt; and &lt;response&gt; tags in favour of a more 
		static description of an observation.
	</revision>

	<revision value="2.1">
	        <author>Jason Etherton</author>
		<date>2001.10.30</date>
		As above.
	</revision>
</documentation>
</annotation>
-->

<!--======================== RTML Tag Descriptions =========================-->

<!-- Abstract -->
<!--
<annotation>
<documentation>
	<tagName>Abstract</tagName>
	<tagDescription>
		The short abstract of a <seeTag>Project</seeTag>.
	</tagDescription>
	<tagExample>
		<Abstract>We want lots of observing time for a great project.
		</Abstract>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT Abstract
	(#CDATA)
>

<!--========================================================================-->

<!-- Address -->
<!--
<annotation>
<documentation>
	<tagName>Address</tagName>
	<tagDescription>
		Real mailing address within a <seeTag>Contact</seeTag>.
 	</tagDescription>
	<tagExample>
		<Address>
			Geismarlandstr. 11, 37083 G&ouml;ttingen, Germany
		</Address>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT Address
	(#CDATA)
>

<!--========================================================================-->

<!-- AirmassConstraint -->
<!--
<annotation>
<documentation>
	<tagName>AirmassConstraint</tagName>
	<tagDescription>
		Places contraints on acceptable airmass.  If an
		<seeTag>ExposureFactor</seeTag> tag is included, then the
		nominal <seeTag>Exposure</seeTag> should be corrected
		for the expected decrease in brightness.
		<br></br>
		See <seeTag>Schedule</seeTag>.
	</tagDescription>
	<tagExample>
		<AirmassConstraint minimum="2.9" maximum="3.1">
			Need this standard star at roughly the same airmass!
		</AirmassConstraint>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT AirmassConstraint
	(#CDATA, ExposureFactor?)
>
<!ATTLIST AirmassConstraint
	minimum	CDATA	#IMPLIED
	maximum CDATA	#IMPLIED
>

<!--========================================================================-->

<!-- Altitude -->
<!--
<annotation>
<documentation>
	<tagName>Altitude</tagName>
	<tagDescription>
		Terrestrial altitude, used within a
		<seeTag>Location</seeTag>.
	</tagDescription>
	<tagExample>
		<Altitude units="feet">5432</Altitude>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT Altitude
	(#CDATA)
>
<!ATTLIST Altitude
	format	CDATA           #IMPLIED
	units	%lengthUnits;	#IMPLIED
>

<!--========================================================================-->

<!-- AngleOffset -->
<!--
<annotation>
<documentation>
        <tagName>AngleOffset</tagName>
        <tagDescription>
		An angular offset in some coordinate system determined by the
		parent element in some "units".  Depending upon the units,
		it may be necessary to specify the "format" used.
                <br></br>
                See <seeTag>Coordinates</seeTag>.
        </tagDescription>
        <tagExample>
                <LatCoordinate units="degs">
			+55.4321
			<AngleOffset units="dms" format="sddd mm ss.s">
				-000 01 02.3
			</AngleOffset>
		</LatCoordinate>
        </tagExample>
</documentation>
</annotation>
-->

<!ELEMENT AngleOffset
        (#CDATA)
>
<!ATTLIST AngleOffset
        format  CDATA           #IMPLIED
        units   %angleUnits;    #IMPLIED
>

<!--========================================================================-->

<!-- Aperture -->
<!--
<annotation>
<documentation>
	<tagName>Aperture</tagName>
	<tagDescription>
		Equivalent circular aperture of a <seeTag>Telescope</seeTag>.
	</tagDescription>
	<tagExample>
		<Aperture units="meters">2.4</Aperture>
	</tagExample>
</documentation>
<annotation>
-->

<!ELEMENT Aperture
	(#CDATA)
>
<!ATTLIST Aperture
	units	%lengthUnits;	#REQUIRED
>
 
<!--========================================================================-->

<!-- BadPixels -->
<!--
<annotation>
<documentation>
	<tagName>BadPixels</tagName>
	<tagDescription>
		This element within a
		<seeTag>Calibration</seeTag> describes whether the effects
		of bad pixels should be/have been removed.  The content is used to
		provide URL's for data uploads (e.g. images showing the pixels which
		have been corrected.
	</tagDescription>
	<tagExample>
		<BadPixels correct="false" />
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT BadPixels
	(#CDATA)
>
<!ATTLIST BadPixels
	correct	%booleanTypeF;	#IMPLIED
>

<!--========================================================================-->

<!-- Bias -->
<!--
<annotation>
<documentation>
	<tagName>Bias</tagName>
	<tagDescription>
		In an RTML request, this element within a
		<seeTag>Calibration</seeTag> describes whether the bias should
		be corrected for (overscan and/or mean pattern bias).  The
		"correct" attribute is for non-specific corrections, whereas
		the "overscan" and "mean" attributes refer to more specific
		corrections. The content is used to provide URL's for data
		uploads.  The "number" attribute suggests/informs how many
		exposures should be/were used to perform the calibration.
	</tagDescription>
	<tagExample>
		Here's a request-mode bias element:

		<Bias overscan="true" mean="false" />
	</tagExample>
	<tagExample>
		Here's a report-mode bias element:

		<Bias correct="true" number="5">
		ftp://ftp.monet.uni-sw.gwdg.de/pub/data/2002/05/bias22.fits
		</Bias>

		The same element with correct="false" would indicate that
		no correction was made, but also where the mean bias frame
		could be obtained to make the correction.
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT Bias
	(#CDATA)
>
<!ATTLIST Bias
	correct		%booleanTypeT;	#IMPLIED
	overscan	%booleanTypeT;	#IMPLIED
	mean		%booleanTypeT;	#IMPLIED
	number		CDATA		#IMPLIED
>

<!--========================================================================-->

<!-- Binning -->
<!--
<annotation>
<documentation>
	<tagName>Binning</tagName>
	<tagDescription>
		The amount of pixel binning which is to be used in a detector.
		<br></br>
		See <seeTag>Detector</seeTag>.
	</tagDescription>
	<tagExample>
		<Binning rows="1" columns="4" />
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT Binning
	(#CDATA)
>
<!ATTLIST Binning
	rows	#CDATA	#IMPLIED
	columns	#CDATA	#IMPLIED
>

<!--========================================================================-->

<!-- Calibration -->
<!--
<annotation>
<documentation>
	<tagName>Calibration</tagName>
	<tagDescription>
		Describes what calibration measures should be performed on
		or for the final <seeTag>Observation</seeTag>.
		The content of the (optional) calibration
		daughter elements is used to provide URL's for data uploads.
		<br></br>
		See <seeTag>Bias</seeTag>,
		<seeTag>DarkCurrent</seeTag>,
		<seeTag>BadPixels</seeTag>,
		<seeTag>FlatField</seeTag>,
		<seeTag>Fringing</seeTag>,  and
		<seeTag>CosmicRays</seeTag>.
	</tagDescription>
	<tagExample>
		Here is a request for calibrations (anything which isn't mentioned
		is assumed to be defaulted to correct="no":

		<Calibration>
			<Bias correct="yes" />
			<DarkCurrent correct="yes" />
			<FlatField correct="yes" sky="yes" />
		</Calibration>
	</tagExample>
	<tagExample>
		Here is the result of a set of calibrations:

		<Calibration>
			<Bias correct="yes" number="10">
				ftp://ftp.observatory.net/pub/calib/bias/b1234567.fits
			</Bias>
			<DarkCurrent correct="yes" />
				ftp://ftp.observatory.net/pub/calib/dark/d1234567.fits
			</DarkCurrent>
			<BadPixels correct="no" />
			<FlatField correct="yes" sky="yes" number="5">
				ftp://ftp.observatory.net/pub/calib/flats/f1234567.fits
			</FlatField>
			<Fringing correct="no" />
			<CosmicRays correct="no" />
		</Calibration>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT Calibration
	(Bias?, DarkCurrent?, BadPixels?, FlatField?, Fringing?, CosmicRays?)
>

<!--========================================================================-->

<!-- Capacity -->
<!--
<annotation>
<documentation>
	<tagName>Capacity</tagName>
	<tagDescription>
	The maximum amount of signal in a
	<seeTag>Detector</seeTag>.  This can either be a total
	number of counts (e.g. for an integrating detector) or a maximum count
	rate (e.g. for a photon-counting detector).
	</tagDescription>
	<tagExample>
		<Capacity units="cts/sec">100000</Capacity>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT Capacity
	(#CDATA)
>
<!ATTLIST Capacity
	units CDATA #IMPLIED
>

<!--========================================================================-->

<!-- ColumnPixelSize -->
<!--
<annotation>
<documentation>
	<tagName>ColumnPixelSize</tagName>
	<tagDescription>
	Size of the pixels in the horizontal direction (w.r.t. the final
	image -
	"how wide are the columns?") in some units (default is microns)
	for a <seeTag>Detector</seeTag>. The
	pixels are assumed to be non-square.
	<br></br>
	See <seeTag>PixelRadius</seeTag>,
	<seeTag>RowPixelSize</seeTag>, and
	<seeTag>PixelSize</seeTag>
	</tagDescription>
	<tagExample>
		<ColumnPixelSize units="microns">
			15.0
		</ColumnPixelSize>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT ColumnPixelSize
	(#CDATA)
>
<!ATTLIST ColumnPixelSize
	units %lengthTypes; #IMPLIED
>

<!--========================================================================-->

<!-- Contact -->
<!--
<annotation>
<documentation>
	<tagName>Contact</tagName>
	<tagDescription>
		<p>
		Normally, an RTML document body begins with the &lt;Contact&gt;
		tag.  This contains contact information for the transaction,
		perhaps both about the client(s) and the server.
		If several clients are involved, then each should have his/her
		own &lt;Contact&gt;.  The "PI" attribute is either ignored or
		equal to "true" (for the Principle Investigator of a project)
		or "false" (for a Co-PI).
		</p>
		<p>
		The attribute "ident" is an ASCII string used as a short-cut:
		generally these should be given by the server to the client(s).
		</p>
		<p>
		<br></br>
		See <seeTag>User</seeTag>,
		<seeTag>Name</seeTag>,
		<seeTag>Institution</seeTag>,
		<seeTag>Address</seeTag>,
		<seeTag>Telephone</seeTag>,
		<seeTag>Fax</seeTag>,
		<seeTag>Email</seeTag>,
		<seeTag>Url</seeTag>, and
		<seeTag>TimeCharge</seeTag>
		</p>
	</tagDescription>
	<tagExample>
		<Contact ident="ae12345" />
	</tagExample>
	<tagExample>
		<Contact PI="yes">
			<User>aeinste</User>
			<Name>A. Einstein</Name>
			<Institution type="university">Princeton Univ.</Institution>
			<Address>Jadwin Hall, PO Box 708, Princeton, NJ, USA 08544-0708</Address>
			<Telephone>+1-609-258-4400</Telephone>
			<Fax>+1-609-258-1124</Fax>
			<Email>aeinste@princeton.edu</Email>
			<Url>http://www.phys.princeton.edu</Url>
			<TimeCharge time="2.0" units="hours" />
		</Contact>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT Contact
	(#CDATA, User, Name, Institution, Address, Telephone, Fax, Email, Url, TimeCharge)
>
<!ATTLIST Contact
	ident CDATA		#IMPLIED
	PI    %booleanTypeT;	#IMPLIED
>

<!--========================================================================-->

<!-- Coordinates -->
<!--
<annotation>
<documentation>
	<tagName>Coordinates</tagName>
	<tagDescription>
		An element containing astronomical coordinates - either a
		<seeTag>RightAscension</seeTag>, <seeTag>Declination</seeTag>
		and an <seeTag>Equinox</seeTag> or a longitude-like coordinate
		(<seeTag>LongCoordinate</seeTag>), a latitude-like coordinate
		(<seeTag>LatCoordinate</seeTag>) and an
		<seeTag>Equinox</seeTag>.  All coordinates can be expressed in
		any of the <seeEntity>angleUnits</seeEntity> and with any
		(given) format.  An <seeTag>Epoch</seeTag> is optional and
		is otherwise
		assumed to be equal to the <seeTag>Equinox</seeTag>.
		<p>
		In order to make it possible to observe very faint objects, it
		is possible to input <seeTag>AngleOffset</seeTag>'s within the
		individual coordinates.  The assumption is that the original
		coordinates refer to some other object which can be aquired and
		centered, so that the final position with offsets may refer
		to an apparently blank patch of sky.
		</p>
		<p>
		The "format" syntax is mostly for giving coordinates in
		the form hh:mm:ss.ss etc.  The abbreviations are
		"s"=sign (only if at the very beginning),
		"h"=hours_digit, "d"=degrees_digit,"m"=(arc)minutes_digit,
		"s"=(arc)seconds_digits (also used for and to indicate the
		number
		of decimal places).  Other text can be used in the format
		if appropriate:  e.g.  format="Latitude sddd mm ss.ss".
		The letters "s", "h", "d", and "m" which should be interpreted
		as normal non-formating letters can be indicated by a backslash:
		e.g. format="Longitude hh\h mm\m ss\s E" to express the format
		of the content "Longitude 12h 34m 56s E".
		</p>
	</tagDescription>
	<tagExample>
		<Coordinates>
			<RightAscension format="hh:mm:ss.dd">
				12:34:56.78
			</RightAscension>
			<Declination format="sdd mm ss.dd">
				-76 54 32.10
			</Declination>
			<Equinox>2000</Equinox>
		</Coordinates>
	</tagExample>
	<tagExample>
		<Coordinates type="galactic">
			Here's an object in galactic coordinates which is
			offset by -10.5 arcseconds in galatic latitude.
			<LongCoordinate units="degrees">-145.63</LongCoordinate>
			<LatCoordinateunits="degs">
				+12.342
				<AngleOffset units="arcsecs">-10.5</AngleOffset>
			</LatCoordinate>
			<Equinox>2000</Equinox>
		</Coordinates>
	</tagExample>
	<tagExample>
		<Coordinates type="equatorial">
			Nearly the same as first example above!
			<LongCoordinate format="hh:mm:ss.dd">
				12:34:56.78
			</LongCoordinate>
			<LatCoordinate format="sdd:mm:ss">
				-76:54:32
			</LatCoordinate>
			<Equinox>2000</Equinox>
		</Coordinates>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT Coordinates
	(#CDATA, ((RightAscension, Declination)|(LongCoordinate, LatCoordinate)), Equinox, Epoch?)
>
<!ATTLIST Coordinates
	type	%coordinateTypes;	#IMPLIED
>

<!--========================================================================-->

<!-- CosmicRays -->
<!--
<annotation>
<documentation>
	<tagName>CosmicRays</tagName>
	<tagDescription>
		In request mode of a <seeTag>Calibration</seeTag>,
		this element describes whether the cosmic
		rays should be removed.  The content is used to provide
		URL's for data uploads.
	</tagDescription>
	<tagExample>
		<CosmicRays correct="true" />
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT CosmicRays
	(#CDATA)
>
<!ATTLIST CosmicRays
	correct	%booleanTypeF;	#IMPLIED
>

<!--========================================================================-->

<!-- DarkCurrent -->
<!--
<annotation>
<documentation>
	<tagName>DarkCurrent</tagName>
	<tagDescription>
		In request mode of a <seeTag>Calibration</seeTag>,
		this element describes whether the dark
		current should be removed.  The content is used to provide
		URL's for data uploads.
		The "number" attribute suggests/informs how many exposures
		should be/were used to perform the calibration.
	</tagDescription>
	<tagExample>
		<DarkCurrent correct="true" />
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT DarkCurrent
	(#CDATA)
>
<!ATTLIST DarkCurrent
	correct	%booleanTypeT;	#IMPLIED
	number	CDATA		#IMPLIED
>

<!--========================================================================-->

<!-- DarkRate -->
<!--
<annotation>
<documentation>
	<tagName>DarkRate</tagName>
	<tagDescription>
	The rate at which background counts are added to the image during an
	exposure by a <seeTag>Detector</seeTag> (usually thermal).
	</tagDescription>
	<tagExample>
		<DarkRate units="e-/s">0.01</DarkRate>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT DarkRate
	(#CDATA)
>
<!ATTLIST DarkRate
	units CDATA #IMPLIED
>

<!--========================================================================-->

<!-- Databank -->
<!--
<annotation>
<documentation>
	<tagName>Databank</tagName>
	<tagDescription>
		A virtual observation which can be obtained using
		previously carried out observations,
		but can be accessed using the normal RTML
		syntax (using dates in the past, for example).
		<br></br>
		See <seeTag>Target</seeTag>,
		<seeTag>Telescope</seeTag>,
		<seeTag>Observation</seeTag>,
		<seeTag>Project</seeTag>, and
		<seeTag>Contact</seeTag>
	</tagDescription>
	<tagExample>
		<RTML type="request">
			.....
			<Databank region="visual">
				<Target>
					<TargetName>M31</TargetName>
				</Target>
				<Observation>
					....
				</Observation>
			</Databank>
		</RTMl2>
	</tagExample>
</documentation>
<annotation>
-->

<!ELEMENT Databank
	(Target?, Telescope?, Observation?, Project?, Contact?)
>
<!ATTLIST Databank
	name	CDATA			#IMPLIED
	region	%spectralRegions;	#IMPLIED
>
 
<!--========================================================================-->

<!-- Declination -->
<!--
<annotation>
<documentation>
	<tagName>Declination</tagName>
	<tagDescription>
		An equatorial celestial coordinate (same as
		&lt;LatCoordinate type="equatorial"&gt;).
		<br></br>
		See <seeTag>Coordinates</seeTag> and
		<seeTag>AngleOffset</seeTag>.
	</tagDescription>
	<tagExample>
		<Declination format="sddd mm sss.ss" units="dms">
			-123 45 43.21
		</Declination>
	</tagExample>
	<tagExample>
		<Declination units="degs">
			-123.4567
		</Declination>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT Declination
	(#CDATA, AngleOffset)
>
<!ATTLIST Declination
	format	CDATA		#IMPLIED
	units	%angleUnits;	#IMPLIED
>

<!--========================================================================-->

<!-- Detector -->
<!--
<annotation>
<documentation>
	<tagName>Detector</tagName>
	<tagDescription>
		A general detector for an astronomical instrument. The size of
		the pixels is given either as a <seeTag>PixelSize</seeTag>, a
		<seeTag>PixelRadius</seeTag>, or both a
		<seeTag>ColumnPixelSize</seeTag> and a
		<seeTag>RowPixelSize</seeTag>;. If <seeTag>PixelRadius</seeTag>
		is given, the detector is assumed to be circular.
		The non-trivial units of the detector properties (e.g.
		"e-/count") are not yet prescribed (e.g.
		<seeTag>Capacity</seeTag> can be in a rate for a photon-counting
		detector or a total number of counts for an integrating
		detector).  If allowed, the pixels of the detector can be
		binned using the <seeTag>Binning</seeTag> element and only 
		part of the pixel array can be read-out/stored using the
		information in the <seeTag>Windowing</seeTag> element.
		<br></br>
		See also <seeTag>PositionAngle</seeTag>,
		<seeTag>DarkRate</seeTag>,
		<seeTag>Capacity</seeTag>,
		<seeTag>ReadoutNoise</seeTag>,
		<seeTag>Gain</seeTag>,
		<seeTag>Binning</seeTag>,
		<seeTag>Windowing</seeTag>,
		<seeTag>Device</seeTag>, and
		<seeTag>Telescope</seeTag>.
	</tagDescription>
	<tagExample>
		<Detector numColumns="1" numRows="1">
			Photoelectric phototube
			<PixelRadius units="cm">0.1</PixelRadius>
			<Gain units="e-/count">1</Gain>
			<posAngle units="degs">45.5</posAngle>
			<Capacity units="counts/s">80000</Capacity>
			<ReadoutNoise units="e-">0.0</ReadoutNoise>
		</Detector>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT Detector
	((PixelSize | PixelRadius | (ColumnPixelSize, RowPixelSize))?, PositionAngle?, DarkRate?, Capacity?, ReadoutNoise?, Gain?, Binning?, Windowing?)
>
<!ATTLIST Detector
	numColumns	CDATA	#IMPLIED
	numRows		CDATA	#IMPLIED
>

<!--========================================================================-->

<!-- Device -->
<!--
<annotation>
<documentation>
	<tagName>Device</tagName>
	<tagDescription>
		An RTML device is any instrument or device of interest to a
		client, including astronomical instruments like cameras,
		spectrographs, photometers, etc., as well as auxilliary
		instruments such as weather stations, web-cams, sky-monitors,
		etc.  RTML provides a minimum set of
		<seeEntity>deviceTypes</seeEntity> which should
		cover most needs:
		<table border=1>
			<tr><td>Device</td><td>type=</td></tr>
			<tr><td>direct imaging</td><td>"camera"</td></tr>
			<tr><td>spectroscopy</td><td>"spectrograph"</td></tr>
			<tr><td>photometry</td><td>"photometer"</td></tr>
			<tr><td>polarimetry</td><td>"polarimeter"</td></tr>
			<tr><td>spectropolarimetry</td><td>"spectropolarimeter"</td></tr>
			<tr><td>weather monitoring</td><td>"weatherStation"</td></tr>
			<tr><td>telescope guiding</td><td>"autoGuider"</td></tr>
			<tr><td>Web cameras</td><td>"webCamera"</td></tr>
			<tr><td>(other)</td><td>"other"</td></tr>
		</table>
		<br></br>
		See also <seeTag>Filter</seeTag>,
		<seeTag>Grating</seeTag>, 
		<seeTag>Telescope</seeTag>, and
		<seeTag>Detector</seeTag>.
	</tagDescription>
	<tagExample>
		<Device type="camera" region="optical">CCD Camera #1</Device>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT Device
	(#CDATA, Device*, Filter?, Grating?, Detector*)
>
<!ATTLIST Device
	name	CDATA			#IMPLIED
	region	%spectralRegions;	#IMPLIED
	type	%deviceTypes;		#IMPLIED
>

<!--========================================================================-->

<!-- EffectiveAperture -->
<!--
<annotation>
<documentation>
	<tagName>EffectiveAperture</tagName>
	<tagDescription>
		Effective equivalent circular aperture of a
		<seeTag>Telescope</seeTag>.  This
		can be used to aid in the simulation of observations by
		including the effects of secondary mirror obscuration, missing
		mirror panels, poor coatings, etc.
	</tagDescription>
	<tagExample>
			<EffectiveAperture units="meters">2.2</EffAperture>
	</tagExample>
</documentation>
<annotation>
-->

<!ELEMENT EffectiveAperture
	(#CDATA)
>
<!ATTLIST EffectiveAperture
	units	%lengthUnits;	#REQUIRED
>
 
<!--========================================================================-->

<!-- Email -->
<!--
<annotation>
<documentation>
	<tagName>Email</tagName>
	<tagDescription>
		Electronic mailing address of the form {name}@{address}
		in a <seeTag>Contact</seeTag>.
	</tagDescription>
	<tagExample>
		<Email>hessman@uni-sw.gwdg.de</Email>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT Email
	(#CDATA)
>

<!--========================================================================-->

<!-- EndDateTime -->
<!--
<annotation>
<documentation>
	<tagName>EndDateTime</tagName>
	<tagDescription>
		The end date plus time for a <seeTag>TimeConstraint</seeTag>.
		A format doesn't have to be given since we follow standard
		ISO 8601 formatting rules (e.g. dates are given yyyy.mm.dd,
		times as hh:mm:ss and "dateTimes" as
		yyyy.mm.ddThh:mm:ss{.ss}). This will make RTMLn.0 defined
		by a DTD compatible with later versions defined by XML
		Schema and give us free format checking.
		<br></br>
		See <seeTag>TimeConstraint</seeTag> and
		<seeTag>StartDateTime</seeTag>.
	</tagDescription>
	<tagExample>
		<EndDateTime>2001.06.01T11:00:00</EndDateTime>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT EndDateTime
	(#CDATA)
>

<!--========================================================================-->

<!-- EndPhase -->
<!--
<annotation>
<documentation>
	<tagName>EndPhase</tagName>
	<tagDescription>
		The end phase of a <seeTag>PhaseConstraint</seeTag>.
		May or may not be larger in value than the corresponding
		<seeTag>StartPhase</seeTag>.
	</tagDescription>
	<tagExample>
		<EndPhase>0.2</EndPhase>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT EndPhase
	(#CDATA)
>

<!--========================================================================-->

<!-- Epoch -->
<!--
<annotation>
<documentation>
	<tagName>Epoch</tagName>
	<tagDescription>
		An element containing an astronomical epoch.
		<br></br>
		See <seeTag>Coordinates</seeTag>,
		<seeTag>Equinox</seeTag>.
	</tagDescription>
	<tagExample>
		<Epoch>2000.0</Epoch>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT Epoch
	(#CDATA)
>

<!--========================================================================-->

<!-- Equinox -->
<!--
<annotation>
<documentation>
	<tagName>Equinox</tagName>
	<tagDescription>
		An element containing an astronomical equinox.
		<br></br>
		See <seeTag>Coordinates</seeTag>.
	</tagDescription>
	<tagExample>
		<Equinox>2000.0</Equinox>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT Equinox
	(#CDATA)
>

<!--========================================================================-->

<!-- Exposure -->
<!--
<annotation>
<documentation>
	<tagName>Exposure</tagName>
	<tagDescription>
		The basic exposure time for an
		<seeTag>Observation</seeTag> or for a <seeTag>Schedule</seeTag>.
		The two attributes
		give the time units of the content ("units") and the number of
		exposures ("number").  Defaults should be units="seconds" and
		number="1".  The actual exposure time used can be modified when 
		the tag is located within a <seeTag>Schedule</seeTag> by
		various constraints which have <seeTag>ExposureFactor</seeTag>
		elements, which are multiplied into the basic exposure time
		given here.
	</tagDescription>
	<tagExample>
		<Exposure units="seconds">
		        200
		</Exposure>
		<Exposure type="snr">
		        5.0
		</Exposure>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT Exposure
	(#CDATA)
>
<!ATTLIST Exposure
        type    %exposureType;  #IMPLIED
	units	%timeTypes;	#IMPLIED
	number	CDATA		#IMPLIED
>

<!--========================================================================-->

<!-- ExposureFactor -->
<!--
<annotation>
<documentation>
	<tagName>ExposureFactor</tagName>
	<tagDescription>
		Used by constraints to change the actual exposure time from the
		basic time given by the <seeTag>Exposure</seeTag> element.
		<br></br>
		See also
		<seeTag>Schedule</seeTag>,
		<seeTag>Exposure</seeTag>,
		<seeTag>ExtinctionConstraint</seeTag> and
		<seeTag>PhaseConstraint</seeTag>.
	</tagDescription>
	<tagExample>
		<ExposureFactor>0.1</ExposureFactor>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT ExposureFactor
	(#CDATA)
>

<!--========================================================================-->

<!-- ExtinctionConstraint -->
<!--
<annotation>
<documentation>
	<tagName>ExtinctionConstraint</tagName>
	<tagDescription>
		Places contraints on clouds, either in terms of magnitudes or
		in general terms of cloud type ("clear", "light", "heavy").  If
		an <seeTag>ExposureFactor</seeTag> is included, then the
		nominal <seeTag>Exposure</seeTag> should be corrected for the
		expected loss of light due to the extinction (e.g. obtained
		from monitoring the brightness of guide stars or previously
		observed field/standard stars).
		<br></br>
		See also <seeTag>cloudConstraint</seeTag> and
		<seeTag>Schedule</seeTag>.
	</tagDescription>
	<tagExample>
		<ExtinctionConstraint magnitudes="0.1">
			Doesn't have too be photometric, but also not too bad!
		</ExtinctionConstraint>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT ExtinctionConstraint
	(#CDATA, ExposureFactor?)
>
<!ATTLIST ExtinctionConstraint
	magnitudes	CDATA		#IMPLIED
	clouds		%cloudTypes;	#IMPLIED
>

<!--========================================================================-->

<!-- Fax -->
<!--
<annotation>
<documentation>
	<tagName>Fax</tagName>
	<tagDescription> 
		Facimile number within a <seeTag>Contact</seeTag>,
		including the nation code (+XX) and optional
		numbers for use within the same country (e.g. "(0)").
	</tagDescription>
	<tagExample>
		<Fax>+49-(0)551-39-5043</Fax>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT Fax
	(#CDATA)
>

<!--========================================================================-->

<!-- Filter -->
<!--
<annotation>
<documentation>
	<tagName>Filter</tagName>
	<tagDescription>
		An astronomical filter.  The filter must be defined by either
		a <seeTag>FilterType</seeTag>, a telescope-specific <seeTag>
		FilterNumber</seeTag> or a <seeTag>FilterProfile</seeTag>.
	</tagDescription>
	<tagExample>
		<Filter>
		    <FilterNumber>
		        2
		    </FilterNumber>
		</Filter>
	</tagExample>
	<tagExample>
		<Filter>
		    <FilterProfile wavelength="6563" width="20" units="nm">
		        H&alpha;
		    </FilterProfile>
		</Filter>
	</tagExample>
	<tagExample>
		<Filter>
		    <FilterType type="U" />
		</Filter>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT Filter
        (#CDATA, (FilterNumber|FilterProfile|FilterType))
>

<!--========================================================================-->

<!-- FilterNumber -->
<!--
<annotation>
<documentation>
	<tagName>FilterNumber</tagName>
	<tagDescription>
		An astronomical filter.  The filter must be defined by the
		number of that filter at the telescope.
		<seeTag>Filter</seeTag>
	</tagDescription>
	<tagExample>
	    <FilterNumber>
	        2
	    </FilterNumber>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT FilterNumber
        (#CDATA)
>

<!--========================================================================-->

<!-- FilterProfile -->
<!--
<annotation>
<documentation>
	<tagName>FilterProfile</tagName>
	<tagDescription>
		An astronomical filter.  The filter must be defined by the
		number of that filter at the telescope.
		<seeTag>Filter</seeTag>
	</tagDescription>
	<tagExample>
	<tagExample>
	    <FilterProfile wavelength="6563" width="20" units="nm">
	        H&alpha;
	    </FilterProfile>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT FilterProfile
        (#CDATA)
>

<!ATTLIST FilterProfile
	wavelength	CDATA		#REQUIRED
	width		CDATA		#REQUIRED
	units		%lengthTypes;	#REQUIRED
>

<!--========================================================================-->

<!-- FilterType -->
<!--
<annotation>
<documentation>
	<tagName>FilterType</tagName>
	<tagDescription>
		An astronomical filter.  The filter is be defined by the
		standard filter sets.
		<seeTag>Filter</seeTag>
	</tagDescription>
	<tagExample>
		<Filter>
		    <FilterType type="B-Johnson" />
		</Filter>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT FilterType
        (#CDATA)
>

<!ATTLIST FilterType
	type		%filterTypes;	#IMPLIED
>

<!--========================================================================-->

<!-- FITSHeader -->
<!--
<annotation>
<documentation>
	<tagName>FITSHeader</tagName>
	<tagDescription>
		A simple element containing part or all of the FITS header
		for an astronomical image.  The "type" attribute determines
		whether just the most important ("minimum"), the standard
		("standard") or all the FITS keywords ("all") are shown.
		<br></br>
		See also <seeTag>ImageData</seeTag>.
	</tagDescription>
	<tagExample>
		<FITSHeader>
			SIMPLE = T
			NAXIS  = 2
			NAXIS1 = 1024
			NAXIS2 = 2048
		</FITSHeader>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT FITSHeader
	(#CDATA)
>
<!ATTLIST FITSHeader
	type		%headerTypes;	#REQUIRED
>

<!--========================================================================-->

<!-- FlatField -->
<!--
<annotation>
<documentation>
	<tagName>FlatField</tagName>
	<tagDescription>
		In request mode, this element within a
		<seeTag>Calibration</seeTag> describes whether the flat field
		effects should be removed.  For camera images, this can either
		be done using a skyflat (sky="true") and/or a dome flat
		(dome="true").  The content is used to provide URL's for data
		uploads.
		The "number" attribute suggests/informs how many exposures
		should be/were used to perform the calibration.
	</tagDescription>
	<tagExample>
		<FlatField correct="true" />
	</tagExample>
	<tagExample>
		<FlatField correct="true" sky="true" number="5" />
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT FlatField
	(#CDATA)
>
<!ATTLIST FlatField
	correct	%booleanTypeT;	#IMPLIED
	sky	%booleanTypeF;	#IMPLIED
	dome	%booleanTypeT;	#IMPLIED
	number	CDATA		#IMPLIED
>

<!--========================================================================-->

<!-- Flux -->
<!--
<annotation>
<documentation>
	<tagName>Flux</tagName>
	<tagDescription>
		The flux or brightness of some "type" for a
		<seeTag>Target</seeTag> at some "wavelength" or "frequency"
		and in some "units".  The "wavelengths" may also be
		given as filter names.
		<bugs>The attributes should be more specified!</bugs>
	</tagDescription>
	<tagExample>
		<Flux	type="continuum"
			wavelength="R-Johnson"
			units="mags">19.2</Flux>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT Flux
	(#CDATA)
>
<!ATTLIST Flux
	type		%fluxTypes;	#IMPLIED
	wavelength	CDATA		#IMPLIED
	frequency	CDATA		#IMPLIED
	units		CDATA		#IMPLIED
>

<!--========================================================================-->

<!-- FocalLength -->
<!--
<annotation>
<documentation>
	<tagName>FocalLength</tagName>
	<tagDescription>
		Effective focal length of a <seeTag>Telescope</seeTag>.
	</tagDescription>
	<tagExample>
		<FocalLength units="mm">57600</FocalLength>
	</tagExample>
</documentation>
<annotation>
-->

<!ELEMENT FocalLength
	(#CDATA)
>
<!ATTLIST FocalLength
	units	%lengthUnits;	#REQUIRED
>
 
<!--========================================================================-->

<!-- FocalRatio -->
<!--
<annotation>
<documentation>
	<tagName>FocalRatio</tagName>
	<tagDescription>
		Effective focal-ratio ("f-number") of a
		<seeTag>Telescope</seeTag>, given by
		the ratio of <seeTag>FocalLength</seeTag> to
		the <seeTag>Aperture</seeTag>.
	</tagDescription>
	<tagExample>
		<FocalRatio>f/24</FocalRatio>
	</tagExample>
</documentation>
<annotation>
-->

<!ELEMENT FocalRatio
	(#CDATA)
>
 
<!--========================================================================-->

<!-- Fringing -->
<!--
<annotation>
<documentation>
	<tagName>Fringing</tagName>
	<tagDescription>
		In request mode, this element within a
		<seeTag>Calibration</seeTag> describes whether any fringe
		pattern not removable by flat-fielding should be corrected
		for.  The content is used to provide URL's for data uploads.
	</tagDescription>
	<tagExample>
		<Fringing correct="true" />
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT Fringing
	(#CDATA)
>
<!ATTLIST Fringing
	correct	%booleanTypeT;	#IMPLIED
>

<!--========================================================================-->

<!-- Gain -->
<!--
<annotation>
<documentation>
	<tagName>Gain</tagName>
	<tagDescription>
	The conversion of counts in the final result/image from a
	<seeTag>Detector</seeTag> to the number of
	photons (electrons) actually detected.  The gain of CCD cameras is
	typically a few whereas it is exactly 1 for a pulse-counting
	photometer.
	</tagDescription>
	<tagExample>
		<Gain units="e-/count">3.5</Gain>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT Gain
	(#CDATA)
>
<!ATTLIST Gain
	units CDATA #IMPLIED
>

<!--========================================================================-->

<!-- Grating -->
<!--
<annotation>
<documentation>
	<tagName>Grating</tagName>
	<tagDescription>
		This element describes a grating, prism, grism or similar
		device used in a spectrograph, described by its central
		"wavelength" in some "units", an "angle" (setable random or
		unknown units, not the blaze angle!), an "order", a
		"name", and a "resolution" (&lambda;/&Delta;&lambda;).
		<br></br>
		See <seeTag>Device</seeTag>.
	</tagDescription>
	<tagExample>
		<Grating
			name="GR#1"
			wavelength="650" units="nm"
			resolution="1540"
			angle="12345"
		/>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT Grating
	(#CDATA)
>
<!ATTLIST Grating
	name		CDATA		#IMPLIED
	wavelength	CDATA		#IMPLIED
	units		%lengthUnits;	#IMPLIED
	resolution	CDATA		#IMPLIED
	order		CDATA		#IMPLIED
	angle		CDATA		#IMPLIED
>

<!--========================================================================-->

<!-- ImageData -->
<!--
<annotation>
<documentation>
	<tagName>ImageData</tagName>
	<tagDescription>
		In a request, this element describes what form the image
		data resulting from an observation should take (e.g. 16 bit
		FITS), whether compression should be used (e.g.
		compress="gzip"), and how the image should be delivered
		(e.g. delivery="ftp").

		In RTML document of type "information", this element also can
		be used to provide a URL
		to the data for data uploads.  A report could include the
		<seeTag>Contact</seeTag> or
		<seeTag>Observation</seeTag> element with all of the
		information concerning how the image was triggered or made.
		<br></br>
		See <seeTag>FITSHeader</seeTag>,
		<seeEntity>imageTypes</seeEntity>, and
		<seeEntity>deliveryTypes</seeEntity>.
	</tagDescription>
	<tagExample>
		Here is a request for a FITS image in 16-bit format and
		compressed with the GNU zip algorithm which should
		be uploadable via ftp when it's available.

		<RTML type="request">
		....
		<ImageData
			type="FITS16"
			compressed="gzip"
			delivery="ftp"
		/>
		....
		</RTML>
	</tagExample>
	<tagExample>
		Here is a report on an image which is in some standard
		(but unspecified) FITS format and has been compressed with
		the HST h-format:

		<RTML type="observation">
			....
			<ImageData type="FITS" compressed="HST" 
                         name="1.fits.hz">
				ftp://ftp.monet.uni-sw.gwdg.de/pub/outgoing/1.fits.hz
				<FITSHeader type="minimum">
					....
				</FITSHeader>
			</ImageData>
			....
		</RTML>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT ImageData
	(#CDATA, FITSHeader?, Contact?, Observation?)
>
<!ATTLIST ImageData
	type		%imageFormats;	#REQUIRED
	compressed	%booleanTypesF;	#IMPLIED
	filename	CDATA		#IMPLIED
	delivery	%deliveryTypes;	#IMPLIED
	type            %imageDataTypes #REQUIRED
>

<!--========================================================================-->

<!-- IntelligentAgent -->
<!--
<annotation>
<documentation>
	<tagName>IntelligentAgent</tagName>
	<tagDescription>
                Description of the Intelligent Agent that produced this
                score/request document.  
	</tagDescription>
	<tagExample>
                <IntelligentAgent host="dn1.ex.ac.uk" port="2345">
                        a unique IA identifier goes here, though maybe the
                        host and port attributes are enough?
                </IntelligentAgent>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT IntelligentAgent
        (#CDATA)
>
<!ATTLIST IntelligentAgent
	host            CDATA           #REQUIRED
	port            CDATA           #REQUIRED
>

<!--========================================================================-->

<!-- Institution -->
<!--
<annotation>
<documentation>
	<tagName>Institution</tagName>
	<tagDescription>
		Name/description of the organizational status of the requesting
		or responding party contained within a
		<seeTag>Contact</seeTag>.
		Can contain, e.g., anchor to a web-site as
		content.  The required attribute "type" must contain one of the
		descriptions of the 8 types of institutions:
		<ul><li>"university"</li><li>"college"</li><li>"school"
		<li>"research"</li><li>"commercial"</li><li>"private"</li>
		<li>"network"</li><li>"other"<li></ul>.
	</tagDescription>
	<tagExample>
		<Institution>
			Universit&auml;ts-Sternwarte G&ouml;ttingen
		</Institution>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT Institution
	(#CDATA)
>
<!ATTLIST Institution
	type	%institutionTypes;	#IMPLIED
>

<!--========================================================================-->

<!-- LatCoordinate -->
<!--
<annotation>
<documentation>
	<tagName>LatCoordinate</tagName>
	<tagDescription>
		A coordinate which behaves like terrestral latitude, i.e. is not
		cyclic and runs from -90 to 90 degrees (for example).
		<br></br>
		See also <seeTag>Coordinates</seeTag>,
		<seeTag>LongCoordinate</seeTag>, and
		<seeTag>AngleOffset</seeTag>.
	</tagDescription>
	<tagExample>
		<LatCoordinate units="degs">+55.4321</LatCoordinate>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT LatCoordinate
	(#CDATA, AngleOffset)
>
<!ATTLIST LatCoordinate
	format	CDATA		#IMPLIED
	units	%angleUnits;	#IMPLIED
>

<!--========================================================================-->

<!-- Latitude -->
<!--
<annotation>
<documentation>
	<tagName>Latitude</tagName>
	<tagDescription>
		Terrestrial latitude within a <seeTag>Location</seeTag>.
	</tagDescription>
	<tagExample>
		<Latitude units="degs">+55.4321</Latitude>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT Latitude
	(#CDATA)
>
<!ATTLIST Latitude
	format	CDATA	#IMPLIED
	units	%angleUnits;	#IMPLIED
>

<!--========================================================================-->

<!-- Location -->
<!--
<annotation>
<documentation>
	<tagName>Location</tagName>
	<tagDescription>
		Detailed description of where a
		<seeTag>Telescope</seeTag> or set of telescopes
		is located. The (optional) format attribute uses the same
		symbols as other elements like
		<seeTag>RightAscension</seeTag> and
		<seeTag>Declination</seeTag>:
		see the discussion for <seeTag>Coordinates</seeTag>.
		<br></br>
		See also <seeTag>Altitude</seeTag>,
		<seeTag>Latitude</seeTag>, and
		<seeTag>Longitude</seeTag>.
	</tagDescription>
	<tagExample>
		<Location>
			<Name>Roque de los Muchachos</Name>
			<Longitude format="sdd mm E" units="dms">
				-17 53 E
			</Longitude>
			<Latitude format="sdd mm ss">+28 45 36</Latitude>
			<Altitude units="m">2395</Altitude>
		</Location>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT Location
	(#CDATA, Latitude?, Longitude?, Altitude?)
>

<!--========================================================================-->

<!-- LongCoordinate -->
<!--
<annotation>
<documentation>
	<tagName>LongCoordinate</tagName>
	<tagDescription>
		An angular coordinate which behaves like terrestrial longitude,
		i.e. is strictly cyclic.
		<br></br>
		See <seeTag>Coordinates</seeTag>,
		<seeTag>LatCoordinate</seeTag>, and
		<seeTag>AngleOffset</seeTag>.
	</tagDescription>
	<tagExample>
		<LongCoordinate format="sddd mm sss.ss" units="dms">
			-123 45 43.21
		</LongCoordinate>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT LongCoordinate
	(#CDATA, AngleOffset)
>
<!ATTLIST LongCoordinate
	format	CDATA		#IMPLIED
	units	%angleUnits;	#IMPLIED
>

<!--========================================================================-->

<!-- Longitude -->
<!--
<annotation>
<documentation>
	<tagName>Longitude</tagName>
	<tagDescription>
		Terrestrial longitude within a <seeTag>Location</seeTag>.
		<br></br>
		See <seeTag>Coordinates</seeTag>.
	</tagDescription>
	<tagExample>
		This example shows how labels can be used along with the
		actual number content: if the format is correct, this should
		be easy to parse.

		<Longitude format="Longitude sddd mm sss.ss E" units="dms">
			Longitude -123 45 43.21 E
		</Longitude>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT Longitude
	(#CDATA)
>
<!ATTLIST Longitude
	format	CDATA	#IMPLIED
	units	%angleUnits;	#IMPLIED
>

<!--========================================================================-->

<!-- MagnitudeFilter -->
<!--
<annotation>
<documentation>
	<tagName>MagnitudeFilter</tagName>
	<tagDescription>
	        Describe an <seeTag>ObjectList</seeTag> in terms of magnitudes.
	</tagDescription>
	<tagExample>
	        Find the 20 brightest stars.
	        <ObjectList number="20" />
		<MagnitudeFilter maximum="maximum" />
	</tagExample>
	<tagExample>
	        Find all objects dimmer than magnitude 15.5 in the J-Band
	        <ObjectList number="all" />
		<MagnitudeFilter maximum="15.5" units="J-mag" />
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT MagnitudeFilter
	(#CDATA)
>
<!ATTLIST MagnitudeFilter
	minimum         CDATA           #IMPLIED
	maximum         CDATA           #IMPLIED
	units           %fluxUnits;     #IMPLIED
>

<!--========================================================================-->

<!-- MoonConstraint -->
<!--
<annotation>
<documentation>
	<tagName>MoonConstraint</tagName>
	<tagDescription>
		Says how much moon is acceptable.The "width" attribute is a
		Lorentzian weight parameter describing how "inacceptable" is
		inacceptable (i.e. if the weight is 0.01, then this is 10x
		better than having a weight of 0.1 and 100x better than being
		at the moon).  Full moon is phase=1.0.   Normally, this tag
		has no content, but the content can be used to comment the
		constraint.
		<br></br>
		See <seeTag>SkyConstraint</seeTag>,
		See <seeTag>Schedule</seeTag>.
	</tagDescription>
	<tagExample>
		<MoonConstraint maxPhase="0.5" distance="45.0" units="degs"
			width="60.0" />
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT MoonConstraint
	(#CDATA)
>
<!ATTLIST MoonConstraint
	maxPhase	CDATA		#IMPLIED
	distance	CDATA		#IMPLIED
	width		CDATA		#IMPLIED
	units		%angleUnits;	#IMPLIED
>

<!--========================================================================-->

<!-- Name -->
<!--
<annotation>
<documentation>
	<tagName>Name</tagName>
	<tagDescription>
		The name of a person/location/telescope within the
		<seeTag>Contact</seeTag>
		<seeTag>Location</seeTag>
		<seeTag>Telescope</seeTag> elements repectively.
	</tagDescription>
	<tagExample>
		<Name>A. Einstein</Name>
		<Location>
		    <Name>
		        Roque de los Muchachos, La Palma
		    </name>
		</location>
		<Telescope>
		    <Name>
		        Liverpool Telescope
		    </Name>
		</Telescope>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT Name
	(#CDATA)
>

<!--========================================================================-->

<!-- Object -->
<!--
<annotation>
<documentation>
	<tagName>Object</tagName>
	<tagDescription>
	        The position of a detected object.
		<seeTag>ObjectList</seeTag>
	</tagDescription>
	<tagExample>
	        <ObjectList>
		    <Object>
		        Info supplied by reduction routines.
		        <RightAscension format="hh mm ss.s" units="hms">
			    12 48 33.2
			</RighAscension>
			<Declination format="sdd mm ss.s" units="dms">
			    +23 44 32.1
			</Declination>
			<Flux>
			    Flux not known.
			</Flux>
		    </Object>
	        </ObjectList>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT Object
	(#CDATA, RightAscension, Declination, Flux)
>

<!--========================================================================-->

<!-- ObjectList -->
<!--
<annotation>
<documentation>
	<tagName>ObjectList</tagName>
	<tagDescription>
	        Specify the details of an ObjectList.
		<br>
		Inclusion of both a <seeTag>MagnitudeFilter</seeTag> and a
		<seeTag>PositionFilter</seeTag> will apply both criteria to the
		ObjectList.
	</tagDescription>
	<tagExample>
		<Reduction>
	        Create an object list with magnitudes and position of 
		the 20 brightest objects on frame.
		    <ObjectList number="20" />
	 	    <MagnitudeFilter maximum="maximum" />
		</Reduction>
	</tagExample>
	<tagExample>
		<Reduction>
	            Create an object list with of the magnitude and position of
		    the closest star to 12h 48m 33.2s +23d 44m 32.1s
		    <ObjectList number="1" />
		    <MagnitudeFilter />
		    <PositionFilter radius="0">
		        <RightAscension format="hh mm ss.s" units="hms">
			    12 48 33.2
			</RighAscension>
			<Declination format="sdd mm ss.s" units="dms">
			    +23 44 32.1
			</Declination>
		    </PositionFilter>
		</Reduction>
	</tagExample>
	<tagExample>
		<Reduction>
		        Return an object list with magnitudes and position of 
			the all objects within 5 arcseconds of 
			12h 48m 33.2s +23d 44m 32.1s
			<PositionFilter radius="5" units="arcsec">
		            <RightAscension format="hh mm ss.s" units="hms">
			        12 48 33.2
			    </RighAscension>
			    <Declination format="sdd mm ss.s" units="dms">
			        +23 44 32.1
			    </Declination>
		        </PositionFilter>
			<ObjectList number="all">
			    <Object>
		                <RightAscension format="hh mm ss.s" units="hms">
			            12 48 37.6
				</RighAscension>
			        <Declination format="sdd mm ss.s" units="dms">
			            +23 44 38.4
			        </Declination>
		                <RightAscension format="hh mm ss.s" units="hms">
			            12 48 40.0
				</RighAscension>
			        <Declination format="sdd mm ss.s" units="dms">
			            +23 44 28.8
			        </Declination>
		                <RightAscension format="hh mm ss.s" units="hms">
			            12 48 20.9
				</RighAscension>
			        <Declination format="sdd mm ss.s" units="dms">
			            +23 44 49.6
			        </Declination>
			    </Object>
			</ObjectList>
		</Reduction>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT ObjectList
	(#CDATA, Object*)
>
<!ATTLIST ObjectList
        number          CDATA            #IMPLIED
	type            %objectListTypes #REQUIRED
        format          CDATA            #IMPLIED
>

<!--========================================================================-->

<!-- Observation -->
<!--
<annotation>
<documentation>
	<tagName>Observation</tagName>
	<tagDescription>
		The RTML element which contains all of the information
		necessary for an observation:<br>
		<ul>
		<li>	an optional description of the purpose for
			the observation (<seeTag>Project</seeTag>);</li>
		<li>
			a <seeTag>Target</seeTag> (with <seeTag>Coordinates</seeTag>
			etc.);</li>
		<li>
			an optional <seeTag>Telescope</seeTag> tag;</li>
		<li>
			an optional <seeTag>Device</seeTag> tag;</li>
		<li>
			an <seeTag>Exposure</seeTag> tag (if there's no complex
			scheduling involved) or a <seeTag>Schedule</seeTag>
			(for more complex scheduling constraints which may also
			bear upon the exposure time(s));</li>
		<li>
			an optional <seeTag>Calibration</seeTag> tag documenting which
			forms of calibration are needed; and</li>
		<li>
			an optional <seeTag>Telemetry</seeTag> tag.</li>
		<li>
			one or more <seeTag>ImageData</seeTag> tags
			containing the information either about the
			desired format of the requested data or all the
			details (including things like the
			<seeTag>FITSHeader</seeTag>) about finished data.
			</li>
		</ul>
		The "status" attribute is used to check for
		the completion status of a single observation: <br></br>
		<table border=1>
		  <tr><th>Status</th><th>Meaning</th></tr>
		  <tr><td>error</td><td>observation has not been performed due
			to some error</td></tr>
		  <tr><td>pending</td><td>observation has not been performed but
			is still in the queue</td></tr>
		  <tr><td>incomplete</td><td>observation has not been started but
			is not yet complete (e.g. too few images in a series)
			</td></tr>
		  <tr><td>done</td><td>observation has been performed but the
			data may or may not be available to the client</td></tr>
		  <tr><td>available</td><td>observation has been performed and
			the data are available</td></tr>
		  <tr><td>finished</td><td>observation has been performed and
			the data have been sent to the client - if such has
			been requested</td></tr>
		</table>
		<br></br>
		See also <seeTag>Device</seeTag>,
		<seeEntity>statusTypes</seeEntity>,
		<seeTag>Calibration</seeTag>, and
		<seeTag>Telemetry</seeTag>.
	</tagDescription>
	<tagExample>
		<Observation>
			<Project>Images of M31 would be especially nice.</Project>
			<Device name="CCD Camera #1">
				<Filter type="Johnson-B" />
			</Device>
			<Target ident="target1">
				<TargetName>M31</TargetName>
				<Coordinates>....</Coordinates>
			</Target>
			<Schedule priority="1">
				<Exposure units="minutes">10</Exposure>
			</Schedule>
			<Calibration>
				<Bias             correct="true" />
				<DarkCurrent correct="true" />
				<flat              correct="true" />
			</Calibration>
		</Observation>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT Observation
	(Project?, Target, Telescope?, Device?, (Exposure|Schedule), Calibration?, Reduction?, Telemetry?, ImageData*, ImageData*, ObjectList?)
>
<!ATTLIST Observation
        status  %statusTypes;   #IMPLIED
>

<!--========================================================================-->

<!-- OrbA -->
<!--
<annotation>
<documentation>
	<tagName>OrbA</tagName>
	<tagDescription>
		Semi-major axis of some solar system object (default: A.U.).
		<br></br>
		See <seeTag>OrbitalElements</seeTag>.
	</tagDescription>
	<tagExample>
		<OrbA units="A.U.">2.63969</OrbA>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT OrbA
	(#CDATA)
>
<!ATTLIST OrbA
	units	%lengthUnits;	#IMPLIED
>

<!--========================================================================-->

<!-- OrbE -->
<!--
<annotation>
<documentation>
	<tagName>OrbE</tagName>
	<tagDescription>
		Orbital eccentricity of some solar system object.		
		<br></br>
		See <seeTag>OrbitalElements</seeTag>.
	</tagDescription>
	<tagExample>
		<OrbE>0.26758</OrbE>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT OrbE
	(#CDATA)
>

<!--========================================================================-->

<!-- OrbI -->
<!--
<annotation>
<documentation>
	<tagName>OrbI</tagName>
	<tagDescription>
		Orbital inclination of some solar system object.		
		<br></br>
		See <seeTag>OrbitalElements</seeTag>.
	</tagDescription>
	<tagExample>
		<OrbI units="degs">4.385</OrbI>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT OrbI
	(#CDATA)
>
<!ATTLIST OrbI
	units	%angleUnits;	#IMPLIED
>

<!--========================================================================-->

<!-- OrbitalElements -->
<!--
<annotation>
<documentation>
	<tagName>OrbitalElements</tagName>
	<tagDescription>
		Orbital elements of some solar system object: time of
		perihelion passage <seeTag>OrbT</seeTag>, orbital period
		<seeTag>OrbP</seeTag>, semi-major axis <seeTag>OrbA</seeTag>,
		eccentricity <seeTag>OrbE</seeTag>, inclination
		<seeTag>OrbI</seeTag>, argument of perihelion
		<seeTag>OrbPerihelion</seeTag>, and longitude of ascending
		node <seeTag>OrbNode</seeTag>.		
	</tagDescription>
	<tagExample>
		<OrbitalElements>
			J72TOOE from M.P.E.C. 2001-K37 (2001.5.26)
			<OrbT>2450230.616</OrbT>
			<OrbP units="years">13.7</OrbP>
			<OrbA units="A.U.">2.63969</OrbA>
			<OrbE>0.26758</OrbE>
			<OrbI units="degs">4.385</OrbI>
			<OrbPerihelion units="degs">158.196</OrbPerihelion>
			<OrbNode units="degs">218.734</OrbNode>
		</OrbitalElements>			
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT OrbitalElements
	(#CDATA, OrbT, OrbP, OrbA, OrbE, OrbI, OrbPerihelion, OrbNode)
>

<!--========================================================================-->

<!-- OrbNode -->
<!--
<annotation>
<documentation>
	<tagName>OrbNode</tagName>
	<tagDescription>
		Longitude of ascending node for some solar system object.
		<br></br>
		See <seeTag>OrbitalElements</seeTag>.
	</tagDescription>
	<tagExample>
		<OrbNode>218.734</OrbNode>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT OrbNode
	(#CDATA)
>
<!ATTLIST OrbNode
	units	%angleUnits;	#IMPLIED
>

<!--========================================================================-->

<!-- OrbP -->
<!--
<annotation>
<documentation>
	<tagName>OrbP</tagName>
	<tagDescription>
		Orbital period of some solar system object.  Default is years.
		<br></br>
		See <seeTag>OrbitalElements</seeTag>.
	</tagDescription>
	<tagExample>
		<OrbP units="years">13.7</OrbP>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT OrbP
	(#CDATA)
>
<!ATTLIST OrbP
	units	%timeUnits;	#IMPLIED
>

<!--========================================================================-->

<!-- OrbPerihelion -->
<!--
<annotation>
<documentation>
	<tagName>OrbPerihelion</tagName>
	<tagDescription>
		Argument of perhelion for some solar system object.	
		<br></br>
		See <seeTag>OrbitalElements</seeTag>.
	</tagDescription>
	<tagExample>
		<OrbPerihelion>158.196</OrbPerihelion>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT OrbPerihelion
	(#CDATA)
>
<!ATTLIST OrbPerihelion
	units	%angleUnits;	#IMPLIED
>

<!--========================================================================-->

<!-- OrbT -->
<!--
<annotation>
<documentation>
	<tagName>OrbT</tagName>
	<tagDescription>
		Time of perihelion passage for some solar system object
		(Julian date).
		<br></br>
		See <seeTag>OrbitalElements</seeTag>.
	</tagDescription>
	<tagExample>
		<OrbT>2450230.616</OrbT>
	</OrbitalElements>			
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT OrbT
	(#CDATA)
>

<!--========================================================================-->

<!-- Pair -->
<!--
<annotation>
<documentation>
	<tagName>Pair</tagName>
	<tagDescription>
		A simple, usually comma-separated pair of objects. Used in the
		<seeTag>PointingLimits</seeTag> object to express 
		(altitude,azimuth) pairs.
	</tagDescription>
	<tagExample>
		<Pair>1.2,3.4</Pair>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT Pair
	(#CDATA)
>
<!ATTLIST Pair
	delimeter CDATA #IMPLIED
>

<!--========================================================================-->

<!-- Parallax -->
<!--
<annotation>
<documentation>
	<tagName>Parallax</tagName>
	<tagDescription>
	        The Parallax of the Target in parallax arcseconds.
		<seeTag>Target</seeTag>
	</tagDescription>
	<tagExample>
		<Parallax>
		        1.4
		</Parallax>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT Parallax
	(#CDATA)
>

<!--========================================================================-->

<!-- PhaseConstraint -->
<!--
<annotation>
<documentation>
	<tagName>PhaseConstraint</tagName>
	<tagDescription>
		This constraint insures that the observation will be made
		during a given phase period defined by a quadratic
		ephemeris:
		<br></br>
		&nbsp;&nbsp;&nbsp;
		t = <seeTag>PhaseTime</seeTag> + <seeTag>PhasePeriod</seeTag>*E
		+ 0.5*<seeTag>PhasePeriod</seeTag>*<seeTag>PhasePdot</seeTag>*E*E
		<br></br>
		where E is the period count (a total phase
		usually much larger than 1!).
		<br></br>
		If no <seeTag>ExposureFactor</seeTag> is given, then the
		constraint is to observe ONLY during the given phases.

		The start and end phases can be &lt; or &gt; each other:
		the client and server software using this data should have
		a minimal amount of intelligence and be able to handle
		phases &lt; -1 and &gt; +1.
		<br></br>
		See <seeTag>Schedule</seeTag>,
		<seeTag>StartPhase</seeTag>, and
		<seeTag>EndPhase</seeTag>, and
		<seeTag>ExposureFactor</seeTag>.
	</tagDescription>
	<tagExample>
		<PhaseConstraint>
			Exposure twice as long during as outside the eclipses!
			<PhaseTime units="HJD">2445890.002152</phaseZeroTime>
			<PhasePeriod units="hours">6.54281</PhasePeriod>
			<StartPhase>-0.2</StartPhase>
			<EndPhase>0.2</EndPhase>
			<ExposureFactor>2.0</ExposureFactor>
		</PhaseConstraint>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT PhaseConstraint
	(#CDATA, PhaseTime, PhasePeriod, StartPhase, EndPhase, ExposureFactor?)
>

<!--========================================================================-->

<!-- PhasePeriod -->
<!--
<annotation>
<documentation>
	<tagName>PhasePeriod</tagName>
	<tagDescription>
		Period to be used for a <seeTag>PhaseConstraint</seeTag>.
	</tagDescription>
	<tagExample>
		<PhasePeriod units="hours">6.54281</PhasePeriod>
	</tagExample>
</documentation>
</annotation>
-->
<!ELEMENT PhasePeriod
	(#CDATA)
>
<!ATTLIST PhasePeriod
	units	%timeUnits;	#REQUIRED
>

<!--========================================================================-->

<!-- PhasePdot -->
<!--
<annotation>
<documentation>
	<tagName>PhasePdot</tagName>
	<tagDescription>
		Rate of change of the period used in a
		<seeTag>PhaseConstraint</seeTag> (assumed to
		be in the same
		units as <seeTag>PhasePeriod</seeTag> so that
		it is unitless).
	</tagDescription>
	<tagExample>
		<PhasePdot>-1.e-12</PhasePdot>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT PhasePdot
	(#CDATA)
>

<!--========================================================================-->

<!-- PhaseTime -->
<!--
<annotation>
<documentation>
	<tagName>PhaseTime</tagName>
	<tagDescription>
		Zero point of an ephemeris for a
		<seeTag>PhaseConstraint</seeTag>.
	</tagDescription>
	<tagExample>
		<PhaseTime units="HJD">2445890.002152</phaseZeroTime>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT PhaseTime
	(#CDATA)
>
<!ATTLIST PhaseTime
	units	%timeUnits;	#REQUIRED
>

<!--========================================================================-->

<!-- PixelRadius -->
<!--
<annotation>
<documentation>
	<tagName>PixelRadius</tagName>
	<tagDescription>
	Size of pixels in a <seeTag>Detector</seeTag>
	in some units (default is microns).  The pixels are
	assumed to be circular.
	<br></br>
	See <seeTag>PixelSize</seeTag>,
	<seeTag>RowPixelSize</seeTag>, and
	<seeTag>ColumnPixelSize</seeTag>.
	</tagDescription>
	<tagExample>
		<PixelRadius units="cm">0.78</PixelRadius>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT PixelRadius
	(#CDATA)
>
<!ATTLIST PixelRadius
	units %lengthTypes; #IMPLIED
>

<!--========================================================================-->

<!-- PixelSize -->
<!--
<annotation>
<documentation>
	<tagName>PixelSize</tagName>
	<tagDescription>
	Size of pixels in a <seeTag>Detector</seeTag>
	in some units (default is microns).  The pixels are
	assumed to be square.
	<br></br>
	See <seeTag>PixelRadius</seeTag>,
	<seeTag>RowPixelSize</seeTag>, and
	<seeTag>ColumnPixelSize</seeTag>.
	</tagDescription>
	<tagExample>
		<PixelSize units="microns">9</PixelSize>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT PixelSize
	(#CDATA)
>
<!ATTLIST PixelSize
	units %lengthTypes; #IMPLIED
>

<!--========================================================================-->

<!-- PlateScale -->
<!--
<annotation>
<documentation>
	<tagName>PlateScale</tagName>
	<tagDescription>
		The plate scale at the focus of a
		<seeTag>Telescope</seeTag>, given by the
		number of arcseconds in a radian devided by the effective
		focal length in millimeters.  The required
		attribute units must thus be equal to "arcsec/mm".
	</tagDescription>
	<tagExample>
		<PlateScale units="arcsec/mm">3.5810</PlateScale>
	</tagExample>
</documentation>
<annotation>
-->

<!ELEMENT PlateScale
	(#CDATA)
>
<!ATTLIST Telescope
	units "arcsec/mm" #REQUIRED
>
 
<!--========================================================================-->

<!-- PointingLimits -->
<!--
<annotation>
<documentation>
	<tagName>PointingLimits</tagName>
	<tagDescription>
		Describes the angular limits of the movement of a
		<seeTag>Telescope</seeTag> in
		degrees.If given as a series of <seeTag>Pair</seeTag>'s, the
		assumption is that one can interpolate between.  North is 0
		degs in azimuth and East is 90 degrees.  The attribute
		"zenith" is for alt-az telescopes which cannot observe near
		the zenith. The attributes "sun", "moon", and "earth" are
		given, e.g., for the avoidance zones of spacecraft.
	</tagDescription>
	<tagExample>
		<PointingLimits zenith="0.5">
			There's a big tree off to the NNE near our
			alt-az telescope!
			<Pair>0,0</Pair>
			<Pair>10,20</Pair>
			<Pair>30,25</Pair>
			<Pair>33,0</Pair>
		</PointingLimits>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT PointingLimits
	(#CDATA, Pair*)
>
<!ATTLIST PointingLimits
	zenith	CDATA		#IMPLIED
	sun	CDATA		#IMPLIED
	moon	CDATA		#IMPLIED
	earth	CDATA		#IMPLIED
>

<!--========================================================================-->

<!-- PositionAngle -->
<!--
<annotation>
<documentation>
	<tagName>PositionAngle</tagName>
	<tagDescription>
	Standard astronomical position angle (0 at the north), increasing to the
	celestial east (usually to the left in images) appropriate
	for a <seeTag>Detector</seeTag>.
	</tagDescription>
	<tagExample>
		<PositionAngle units="degs">156.7</PositionAngle>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT PositionAngle
	(#CDATA)
>
<!ATTLIST PositionAngle
	units %angleTypes; #IMPLIED
>

<!--========================================================================-->

<!-- PositionFilter -->
<!--
<annotation>
<documentation>
	<tagName>PositionFilter</tagName>
	<tagDescription>
	        Describe an <seeTag>ObjectList</seeTag> in terms of position.
	</tagDescription>
	<tagExample>
		<Reduction>
		    Create an object list with positions of all objects within 
		    30 arcseconds of 12h 48m 33.2s +23d 44m 32.1s
		    <ObjectList number="all" />
		    <PositionFilter radius="30" units="arcsec">
			    <RightAscension format="hh mm ss.s" units="hms">
			        12 48 33.2
			    </RighAscension>
			    <Declination format="sdd mm ss.s" units="dms">
			        +23 44 32.1
			    </Declination>
		    </PositionFilter>
		</Reduction>
	</tagExample>
	<tagExample>
		<Reduction>
		    <ObjectList number="20">
		        Create an object list with magnitudes and position of 
			the 20 objects closest to 12h 48m 33.2s +23d 44m 32.1s
		    </ObjectList>
		    <PositionFilter radius="0" units="arcsec">
			    <RightAscension format="hh mm ss.s" units="hms">
			        12 48 33.2
			    </RighAscension>
			    <Declination format="sdd mm ss.s" units="dms">
				+23 44 32.1
			    </Declination>
		    </PositionFilter>
		    <MagnitudeFilter />
		</Reduction>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT PositionFilter
	(#CDATA, (RightAscension, Declination)?)
>
<!ATTLIST PositionFilter 
        radius          CDATA           #IMPLIED
	units           %angleUnits;    #IMPLIED
>

<!--========================================================================-->

<!-- Project -->
<!--
<annotation>
<documentation>
	<tagName>Project</tagName>
	<tagDescription>
		The RTML project elements should contain information describing
		why the request (within an <seeTag>RTML</seeTag> tag) or
		<seeTag>Observation</seeTag> is needed, be it a
		scientific research
		project (using a shortened form of the standard project
		descriptions seen by TACs) or a school project ("We would
		like a nice picture of the moon at phase 0.5 to measure
		crater heights with.").  The "ident" attribute
		given either by the client (e.g. from a TAC) or by the
		server (e.g. in a type="confirmation" document)
		can be used as a short form for the project.
		<br></br>
		See <seeTag>Title</seeTag> and <seeTag>Abstract</seeTag>.
	</tagDescription>
	<tagExample>
		<Project ident="TX01_001">
			<Title>Observations of Mkn123</Title>
			<Abstract>
				Monitoring observations of the SyI galaxy
				in the B and J bands will be used to measure
				the value of Omega_0.
			</Abstract>
			Jones et al. (1999) proposed using the variations in
			AGN's at optical and infrared wavevlengths....
		</Project>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT Project
	(#CDATA, Title?, Abstract?)
>

<!--========================================================================-->

<!-- ProperMotion -->
<!--
<annotation>
<documentation>
	<tagName>ProperMotion</tagName>
	<tagDescription>
		An angular velocity in some coordinate system determined by
		the parent element in some units given by the ratio of the
		<seeEntity>angleUnits</seeEntity> and the
		<seeEntity>timeUnits</seeEntity>.  If the "useEpoch" attribute
		is "true", then the amount of offset is calculated relative
		to the <seeTag>Epoch</seeTag> rather than to the beginning
		of the <seeTag>Observation</seeTag>.
		<br></br>
		See <seeTag>Coordinates</seeTag>.
	</tagDescription>
	<tagExample>
		<Declination units="degs">
			+55.43210234
			<ProperMotion angleunits="arcsec" timeunits="hour">
				-0.01
			</AngleOffset>
		</LatCoordinate>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT ProperMotion
	(#CDATA)
>
<!ATTLIST ProperMotion
	format		CDATA           #IMPLIED
	angleunits	%angleUnits;	#IMPLIED
	timeunits	%timeUnits;	#IMPLIED
	useEpoch        %booleanTypeF;	#IMPLIED
>

<!--========================================================================-->

<!-- RadialVelocity -->
<!--
<annotation>
<documentation>
	<tagName>RadialVelocity</tagName>
	<tagDescription>
		The radial velocity of a <seeTag>Target</seeTag>, expressed
		in some "units" and some "type".
	</tagDescription>
	<tagExample>
		<RadialVelocity type="LSR" units="km/s">-19.2</RadialVelocity>
	</tagExample>
	<tagExample>
		<RadialVelocity units="z">2.54</RadialVelocity>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT RadialVelocity
	(#CDATA)
>
<!ATTLIST RadialVelocity
	type	%velocityTypes;	#IMPLIED
	units	%velocityUnits;	#IMPLIED
>

<!--========================================================================-->

<!-- ReadoutNoise -->
<!--
<annotation>
<documentation>
	<tagName>ReadoutNoise</tagName>
	<tagDescription>
	The mean amount of noise per pixel in a final measurement
	obtained from a <seeTag>Detector</seeTag> solely due to
	the read-out process.
	</tagDescription>
	<tagExample>
		<ReadoutNoise units="counts">1.4</ReadoutNoise>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT ReadoutNoise
	(#CDATA)
>
<!ATTLIST ReadoutNoise
	units CDATA #IMPLIED
>

<!--========================================================================-->

<!-- Reduction -->
<!--
<annotation>
<documentation>
	<tagName>Reduction</tagName>
	<tagDescription>
	Specify that reduction should be carried out on the observation.
	So far the only reduction format is a World Coordinate System solution
	and photometric Magnitudes in an <seeTag>ObjectList</seeTag>.
	</tagDescription>
	<tagExample>
		<Reduction>
		    <ObjectList number="all">
		        Create an object list with Photometry and position of 
			all objects on frame.
		    </ObjectList>
		</Reduction>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT Reduction
	(#CDATA, ObjectList, Magnitude?, Position?)
>

<!--========================================================================-->

<!-- RightAscension -->
<!--
<annotation>
<documentation>
	<tagName>RightAscension</tagName>
	<tagDescription>
		Equatorial celestial coordinate (same as
		&lt;LongCoordinate type="equatorial"&gt;).
		See the description of the format syntax at
		<seeTag>Coordinates</seeTag>.
		<br></br>
		See <seeTag>AngleOffset</seeTag>
	</tagDescription>
	<tagExample>
		<RightAscension format="hh:mm:ss.s" units="hms">
			23:45:43.2
		</RightAscension>
	</tagExample>
	<tagExample>
		<RightAscension format="hh\h mm\m ss.s\s" units="hms">
			23h 45m 43.2s
		</RightAscension>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT RightAscension
	(#CDATA, AngleOffset?)
>
<!ATTLIST RightAscension
	format	CDATA		#IMPLIED
	units	%angleUnits;	#IMPLIED
>

<!--========================================================================-->

<!-- RowPixelSize -->
<!--
<annotation>
<documentation>
	<tagName>RowPixelSize</tagName>
	<tagDescription>
	Size of pixels in the vertical direction
	(w.r.t. the final image - "how
	high are the rows?") in some units (default is microns)
	for some <seeTag>detetctor</seeTag>. The pixels
	are assumed to be non-square (e.g. SBIG ST6).
	<br></br>
	See <seeTag>PixelRadius</seeTag>,
	<seeTag>PixelSize</seeTag>, and
	<seeTag>ColumnPixelSize</seeTag>.
	</tagDescription>
	<tagExample>
		<RowPixelSize units="microns">26.0</RowPixelSize>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT RowPixelSize
	(#CDATA)
>
<!ATTLIST RowPixelSize
	units %lengthTypes; #IMPLIED
>

<!--========================================================================-->

<!-- RTML -->
<!--
<annotation>
<documentation>
	<tagName>RTML</tagName>
	<tagDescription>
		<p>
		Delimits a complete RTML Document consisting of<br></br>
		<ul>
		<li>
			one or more <seeTag>Contact</seeTag>'s;</li>
		<li>
			an optional <seeTag>Project</seeTag> element describing the
			whole project;</li>
		<li>
			an optional <seeTag>Location</seeTag> element giving the
			location of the observatory;</li>
		<li>
			an optional <seeTag>Telescope</seeTag> element specifying
			the telescope to be used;</li>
		<li>
			an optional <seeTag>Databank</seeTag> element if the data
			are being requested from a virtual telescope;</li>
		<li>
			an optional <seeTag>Device</seeTag> element if all observations
			are to be carried out with the same device (e.g. same camera
			and filter);</li>
		<li>
			one or more <seeTag>Observation</seeTag> tags containing all
			of the details (possibly including <seeTag>Device</seeTag>
			elements if each <seeTag>Observation</seeTag> uses different
			devices); and</li>
		<li>
			an optional <seeTag>Calibration</seeTag> element if all calibrations
			are to be carried out the same for all observations.</li>
		</ul>
		</p>
		<p>
		The attribute "version" gives the RTML version number (e.g. "2.0"),
		and the attribute "type" the document mode (one of the
		<seeEntity>rtmlDocumentModes</seeEntity>).  The
		attribute "ident" contains an ASCII string which can be used
		as a short-cut to identify an RTML request/observation; this
		attribute should be created by a server sending a RTML document
		with type "confirmation".  The "timeStamp" attribute contains
		an ISO-conforming date-time which dates an RTML document.
		Finally, the "status" attribute is mainly used to flag errors (e.g. a
		request cannot be confirmed due to errors in syntax, due to
		the inavailability of a certain telescope/instrument configuration,
		or because the telescope is down).
	</tagDescription>
	<tagExample>
		Here's an example of an RTML 2.0 observation request for a default
		telescope - note how there is a project description both at the request
		and observation level and that we could have specified the device outside
		of the <Observation> tags had we used the same filter:

		<RTML version="2.0" type="request">
			<Contact ident="fvh0001" />
			<Project>
				We need some images for our class project.
			</Project>
			<Observation>
				<Project>Images of M31 would be especially nice.</Project>
				<Device name="CCD Camera #1">
					<Filter type="Johnson-B" />
				</Device>
				<Target ident="target1">
					<TargetName>M31</TargetName>
					<Coordinates>....</Coordinates>
				</Target>
				<Schedule priority="1">
					<Exposure units="minutes">10</Exposure>
				</Schedule>
				<Calibration>
					<Bias             correct="true" />
					<DarkCurrent correct="true" />
					<flat              correct="true" />
				</Calibration>
			</Observation>
			<Observation>
				<Project>Red images of an elliptical would be nice.</Project>
				<Device name="CCD Camera #1">
					<Filter type="Johnson-V" />
				</Device>
				<Target ident="target1">
					<TargetName>M32</TargetName>
					<Coordinates>....</Coordinates>
				</Target>
				<Schedule priority="2">
					<Exposure units="minutes">10</Exposure>
				</Schedule>
				<Calibration>
					<Bias             correct="true" />
					<DarkCurrent correct="true" />
					<flat              correct="true" />
				</Calibration>
			</Observation>
		</RTML>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT RTML
	(#CDATA, Contact*, Project?, Location?, Telescope?, Databank*, Device?, Observation*, Calibration?, IntelligentAgent)
>
<!ATTLIST RTML
	version		CDATA			#REQUIRED
	type		%rtmlDocumentModes;	#REQUIRED
	ident		CDATA			#IMPLIED
	timeStamp	CDATA			#IMPLIED
	status		%statusTypes;		#IMPLIED
>

<!--========================================================================-->

<!-- Schedule -->
<!--
<annotation>
<documentation>
	<tagName>Schedule</tagName>
	<tagDescription>
		Defines the constraints on a given
		<seeTag>Observation</seeTag>, both the manner
		in which the observation should be / has been carried out and
		whatever constraints should be / have been taken into
		consideration when carrying out an observation.  The basic
		exposure time is given in the <seeTag>Exposure</seeTag>
		element and the
		other constraint elements modify this exposure 
		(using <seeTag>ExposureFactor</seeTag>'s) based upon
		various conditions.  Multiple constraints of the same type
		are possible
		(e.g. changing the exposure times as function of different
		orbital phases or for different sky brightnesses). The required
		priority attribute is an integer: 0=Target-of-Opportunity
		(highest priority), 1=high priority, 2=lower priority, etc.
		<br></br>
		See <seeTag>Exposure</seeTag>,
		<seeTag>ExposureFactor</seeTag>,
		<seeTag>SeeingConstraint</seeTag>,
		<seeTag>SkyConstraint</seeTag>,
		<seeTag>MoonConstraint</seeTag>,
		<seeTag>ExtinctionConstraint</seeTag>,
		<seeTag>AirmassConstraint</seeTag>,
		<seeTag>TimeConstraint</seeTag>, and
		<seeTag>PhaseConstraint</seeTag>
	</tagDescription>
	<tagExample>
		<Schedule priority="1">
			<Exposure units="minutes">10</Exposure>
			<SeeingConstraint......>...</SeeingConstraint>
			<PhaseConstraint....>...</PhaseConstraint>
			<PhaseConstraint....>...</PhaseConstraint>
		</Schedule>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT Schedule
	(#CDATA, Exposure?, SeeingConstraint*, SkyConstraint*, MoonConstraint*, ExtinctionConstraint*, AirmassConstraint*, TimeConstraint*, PhaseConstraint*)
>
<!ATTLIST Schedule
	priority	CDATA	#REQUIRED
>

<!--========================================================================-->

<!-- SeeingConstraint -->
<!--
<annotation>
<documentation>
	<tagName>SeeingContraint</tagName>
	<tagDescription>
		A simple means of stipulating which seeing is acceptable
		in an RTML <seeTag>Schedule</seeTag>.  Both
		minimum and maximum seeing constraints are available so that
		bad-seeing projects can be defined (e.g. "Make sure you really
		get this image done if the seeing gets this bad!").   Seeing is
		always FWHM in arcseconds!  If an
		<seeTag>ExposureFactor</seeTag>
		is included, the nominal <seeTag>Exposure</seeTag> should be
		modified to correct for the effects of seeing relative to the
		"nominal" seeing (given as the attribute "nominal").  The exact
		method to be used to calculate the correction is left to the
		server.
	</tagDescription>
	<tagExample>
		<SeeingConstraint minimum="4.0" maximum="5.0">
			I really need strange data for a silly project!
		</SeeingConstraint>
	</tagExample>
	<tagExample>
		<Exposure units="secs">10.0</Exposure>
		<SeeingConstraint nominal="1.0" maximum="5.0">
			<ExposureFactor>0.5</ExposureFactor>
			Don't want the exposure to get TOO long, so
			only correct for 1/2 the amount of seeing
			induced exposure lengthening.
		</SeeingConstraint>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT SeeingConstraint
	(#CDATA, ExposureFactor?)
>
<!ATTLIST SeeingConstraint
	minimum	CDATA	#IMPLIED
	maximum	CDATA	#IMPLIED
	nominal	CDATA	#IMPLIED
>

<!--========================================================================-->

<!-- SkyConstraint -->
<!--
<annotation>
<documentation>
	<tagName>SkyConstraint</tagName>
	<tagDescription>
		Like <seeTag>MoonConstraint</seeTag>,
		<seeTag>SkyConstraint</seeTag> says how much moon is
		acceptable, however this time expressed in sky brightness,
		either in terms of a formal intensity (e.g. flux="1.e-20"
		units="...") or as a general description (e.g. attribute
		sky="dark").  The former form needs a "units" attribute.
		Normally, this tag has no content, but the content can be
		used to comment the constraint.
		<br></br>
		See also <seeTag>MoonConstraint</seeTag> and
		<seeTag>Schedule</seeTag>.
	</tagDescription>
	<tagExample>
		<SkyConstraint flux="20.0" units="B-mag/sqr-arcsec"  />
	</tagExample>
	<tagExample>
		<SkyConstraint sky="gray" />
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT SkyConstraint
	(#CDATA)
>
<!ATTLIST SkyConstraint
	sky	%simpleSkyTypes;	#IMPLIED
	value	CDATA			#IMPLIED
	units	%fluxUnits;		#IMPLIED
>

<!--========================================================================-->

<!-- StartDateTime -->
<!--
<annotation>
<documentation>
	<tagName>StartDateTime</tagName>
	<tagDescription>
		The staring date plus time for a
		<seeTag>TimeConstraint</seeTag>.
		A format doesn't have to be given since we follow standard
		ISO 8601 formatting rules (e.g. dates are given yyyy.mm.dd,
		times as hh:mm:ss and "dateTimes" as
		yyyy.mm.ddThh:mm:ss{.ss}). This will make RTMLn.0 defined
		by a DTD compatible with later versions defined by XML
		Schema and give us free format checking.
		<br></br>
		See <seeTag>TimeConstraint</seeTag> and
		<seeTag>EndDateTime</seeTag>.
	</tagDescription>
	<tagExample>
		<StartDateTime>2001.05.29T12:00:00</StartDateTime>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT StartDateTime
	(#CDATA)
>

<!--========================================================================-->

<!-- StartPhase -->
<!--
<annotation>
<documentation>
	<tagName>StartPhase</tagName>
	<tagDescription>
		The beginning phase of a <seeTag>PhaseConstraint</seeTag>.
		May or may not be smaller in value than the corresponding
		<seeTag>EndPhase</seeTag>.
	</tagDescription>
	<tagExample>
		<StartPhase>-0.2</StartPhase>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT StartPhase
	(#CDATA)
>

<!--========================================================================-->

<!-- Target -->
<!--
<annotation>
<documentation>
	<tagName>Target</tagName>
	<tagDescription>
		All of the information needed to point a
		<seeTag>Telescope</seeTag> to an object 
		and track on it.  The "ident" attribute is a client-supplied
		shortcut for accessing information about the source (e.g. "Have
		you looked at HST1_001 yet?").  If a <seeTag>Url</seeTag> is
		given, it is assumed to be for a finder chart.
		<br></br>
		See <seeTag>Coordinates</seeTag>,
		<seeTag>Flux</seeTag>,
		<seeTag>Velocity</seeTag>,
		<seeTag>TrackRate</seeTag>,
		<seeTag>OrbitalElements</seeTag>, and
		<seeTag>Url</seeTag>.
	</tagDescription>
	<tagExample>
		<Target ident="HST1_001">
			Here's a great target!
			<TargetName>M31</TargetName>
			<Coordinates>....</Coordinates>
		</Target>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT Target
	(TargetName*, Coordinates?, Flux?, Velocity?, TrackRate?, OrbitalElements?, Url?)
>
<!ATTLIST Target
	ident	CDATA	#IMPLIED
>

<!--========================================================================-->

<!-- TargetName -->
<!--
<annotation>
<documentation>
	<tagName>TargetName</tagName>
	<tagDescription>
		Standard name of a target (e.g. "M31" "RXJ01234-5678", etc).
	</tagDescription>
	<tagExample>
		<TargetName>M31</TargetName>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT TargetName
	(#CDATA)
>

<!--========================================================================-->

<!-- Telemetry -->
<!--
<annotation>
<documentation>
	<tagName>Telemetry</tagName>
	<tagDescription>
		The RTML element which contains all of the log information 
		created for an <seeTag>Observation</seeTag>.
	</tagDescription>
	<tagExample>
		<Telemetry>
			Time            Event                   Status
			=======================================================
			00:10:00        Exposure started        60sec
			00:11:30        CCD readout             OK
			00:11:35        Exposure started        60sec
			00:13:05        CCD readout             OK
			00:14:35        Exposure started        60sec
			ERROR:  your Win98 computer has lost its connection to
			the keyboard - please type <ENTER> in order to reboot
			without substantial data loss!
		</Telemetry>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT Telemetry
	(#CDATA)
>

<!--========================================================================-->

<!-- Telephone -->
<!--
<annotation>
<documentation>
	<tagName>Telephone</tagName>
	<tagDescription>
		Telephone number within a <seeTag>Contact</seeTag>
		element, including the nation code (+XX) and optional
		numbers for use within the same country (e.g. "(0)").
	</tagDescription>
	<tagExample>
		<Telephone>+1-123-456-7890</Telephone>
	</tagExample>
	<tagExample>
		<Telephone>+49-(0)551-39-5052</Telephone>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT Telephone
	(#CDATA)
>

<!--========================================================================-->

<!-- Telescope -->
<!--
<annotation>
<documentation>
	<tagName>Telescope</tagName>
	<tagDescription>
		Information about a telescope. If no spectral region is given,
		it is assumed to be an optical telescope.
		<br></br>
		See <seeTag>Location</seeTag>,
		<seeTag>Aperture</seeTag>,
		<seeTag>EffectiveAperture</seeTag>,
		<seeTag>FocalLength</seeTag>,
		<seeTag>FocalRatio</seeTag>,
		<seeTag>PlateScale</seeTag>,
		<seeTag>Device</seeTag>, and
		<seeTag>PointingLimits</seeTag>.
	</tagDescription>
	<tagExample>
		<Telescope region="optical" alias="LT">
			<Name>Liverpool Telescope</Name>
			<Aperture units="meters">2.0</Aperture>
			<FocalLength units="mm">20000</FocalLength>
			<FocalRatio>f/10</FocalRatio>
		</Telescope>
	</tagExample>
</documentation>
<annotation>
-->

<!ELEMENT Telescope
	(#CDATA, Name?, Location?, Aperture?, EffectiveAperture?, FocalLength?, FocalRatio?, PlateScale?, Device*, PointingLimits?)
>
<!ATTLIST Telescope
	region	%spectralRegions;	#IMPLIED
	alias	CDATA			#IMPLIED
>
 
<!--========================================================================-->

<!-- TimeCharge -->
<!--
<annotation>
<documentation>
	<tagName>TimeCharge</tagName>
	<tagDescription>
		An element within a <seeTag>Contact</seeTag> which
		is only relevant for multi-user
		requests: the contents describe
		how the successfully used observing time for the requested
		<seeTag>Observation</seeTag>
		is to be charged, given either in percent
		(attribute "percent") or as a real time (attributes "time" and
		"units").If abscent, the time will be charged equally among all
		of the parties with <seeTag>Contact</seeTag>'s. 
	</tagDescription>
	<tagExample>
		<TimeCharge percent="50">
			Time shared equally among G&ouml;ttingen and Texas.
		</TimeCharge>
	</tagExample>
	<tagExample>
		<TimeCharge time="2" units="hours">
 			G&ouml;ttingen only pays for the first 2 hours.
		</TimeCharge>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT TimeCharge
	(#CDATA)
>
<!ATTLIST TimeCharge
	percent	CDATA		#IMPLIED
	time	CDATA		#IMPLIED
	units	%timeUnits;	#IMPLIED
>

<!--========================================================================-->

<!-- TimeConstraint -->
<!--
<annotation>
<documentation>
	<tagName>TimeConstraint</tagName>
	<tagDescription>
		This constraint forces an observation to be made within a
		certain time period given by a
		<seeTag>StartDateTime</seeTag>
		and <seeTag>EndDateTime</seeTag>.
		<br></br>
		See <seeTag>Schedule</seeTag>.
	</tagDescription>
	<tagExample>
		<TimeConstraint>
			Simultaneous observations with XMM.
			<StartDateTime>2001.05.29T12:00:00</StartDateTime>
			<EndDateTime>2001.06.01T11:00:00</EndDateTime>
		</TimeConstraint>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT TimeConstraint
	(#CDATA, StartDateTime, EndDateTime)
>

<!--========================================================================-->

<!-- Title -->
<!--
<annotation>
<documentation>
	<tagName>Title</tagName>
	<tagDescription>
		The title of a <seeTag>Project</seeTag>.
	</tagDescription>
	<tagExample>
		<Title>Observations of Mkn123</Title>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT Title
	(#CDATA)
>

<!--========================================================================-->

<!-- TrackRate -->
<!--
<annotation>
<documentation>
	<tagName>TrackRate</tagName>
	<tagDescription>
		The rate at which a <seeTag>Telescope</seeTag> must
		be tracked in order to
		observe a <seeTag>target</seeTag>.  For solar system
		objects, this can be defined by a set of
		<seeTag>OrbitalElements</seeTag>.
	</tagDescription>
	<tagExample>
		<TrackRate type="siderial" />
	</tagExample>
	<tagExample>
		<TrackRate type="Jupiter" />
	</tagExample>
	<tagExample>
		<TrackRate type="orbital">
			Follow the comet having the following elements.
			<OrbitalElements>...</OrbitalElements>
		</TrackRate>
	</tagExample>
</documentation>
<annotation>
-->

<!ELEMENT TrackRate
	(#CDATA, OrbitalElements?)
>
<!ATTLIST TrackRate
	type	%trackRateTypes;	#IMPLIED
>
 
<!--========================================================================-->

<!-- Url -->
<!--
<annotation>
<documentation>
	<tagName>Url</tagName>
	<tagDescription>
		URL (usually http) where further information may be found
		concerning the &lt;User&gt; or the &lt;Project&gt;.
		<br></br>
		See <seeTag>Contact</seeTag>.
	</tagDescription>
	<tagExample>
		<Url>http://www.uni-sw.gwdg.de/~hessman/MONET</Url>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT Url
	(#CDATA)
>

<!--========================================================================-->

<!-- User -->
<!--
<annotation>
<documentation>
	<tagName>User</tagName>
	<tagDescription>
		Some symbolic name for the party, e.g. a computer userid-like
		name, within a <seeTag>Contact</seeTag>.
	</tagDescription>
	<tagExample>
		<User>USG0001</User>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT User
	(#CDATA)
>

<!--========================================================================-->

<!-- Windowing -->
<!--
<annotation>
<documentation>
	<tagName>Windowing</tagName>
	<tagDescription>
		Determines the pixel sub-array(s) to be used in a
		<seeTag>Detector</seeTag>,
		given as pairs of <seeTag>Pair</seeTag>'s of coordinates
		(lower-left and upper-right).  The lowest-leftest pixel is
		assumed to be at (1,1).
	</tagDescription>
	<tagExample>
		<Windowing><Pair>1,1</Pair><Pair>1024,100</Pair></Windowing>
	</tagExample>
</documentation>
</annotation>
-->

<!ELEMENT Windowing
	(#CDATA, (Pair,Pair)+)
>

<!--======================== RTML Entities =================================-->

<!--========================================================================-->

<!-- %angleUnits -->
<!--
<annotation>
<documentation>
	<entityName>%angleUnits;</entityName>
	<entityDescription>
		Units (with abbreviations) for astronomical angles,
		including the abbreviation "hms" and "dms" for some
		form of (hours,minutes,seconds) and
		(degrees,arcminutes,arcseconds).
	</entityDescription>
</documentation>
</annotation>
-->

<!ENTITY % angleUnits
	"(arcsec|arcsecs|arcseconds|arcmin|arcmins|arcminutes|deg|degs|degrees|rad|rads|radians|hms|dms|HMS|DMS|sec|secs|seconds|min|mins|minutes|hr|hrs|hours)"
>

<!--========================================================================-->

<!-- %booleanTypesT -->
<!--
<annotation>
<documentation>
	<entityName>%booleanTypesT;</entityName>
	<entityDescription>
		Boolean value with default "true".
		<br></br>
		See <seeEntity>booleanTypesF</seeEntity>.
	</entityDescription>
</documentation>
</annotation>
-->

<!ENTITY % booleanTypesT
	"(true|false)"
>

<!--========================================================================-->

<!-- %booleanTypesF -->
<!--
<annotation>
<documentation>
	<entityName>%booleanTypesF;</entityName>
	<entityDescription>
		Boolean value with default "false".
		<br></br>
		See <seeEntity>booleanTypesT</seeEntity>.
	</entityDescription>
</documentation>
</annotation>
-->

<!ENTITY % booleanTypesF
	"(false|true)"
>

<!--========================================================================-->

<!-- %calendarUnits -->
<!--
<annotation>
<documentation>
	<entityName>%calendarUnits;</entityName>
	<entityDescription>
		Time units found in calendar dates.
		<br></br>
		See <seeEntity>timeUnits</seeEntity>.
	</entityDescription>
</documentation>
</annotation>
-->

<!ENTITY % calendarUnits
	"(day|days|mon|month|months|yr|yrs|year|years)"
>

<!--========================================================================-->

<!-- %cloudTypes -->
<!--
<annotation>
<documentation>
	<entityName>%cloudTypes;</entityName>
	<entityDescription>
		Descriptions of cloud cover.
		<br></br>
		See <seeTag>ExtinctionConstraint</seeTag>.
	</entityDescription>
</documentation>
</annotation>
-->

<!ENTITY % cloudTypes
	"(clear|light|heavy)"
>

<!--========================================================================-->

<!-- %compressionTypes -->
<!--
<annotation>
<documentation>
	<entityName>%compressionTypes;</entityName>
	<entityDescription>
		Different types of data compression used to compress
		images.
		<br></br>
		See <seeTag>ImageData</seeTag>.
	</entityDescription>
</documentation>
</annotation>
-->

<!ENTITY % compressionTypes
	"(gzip|zip|compress|hzip)"
>

<!--========================================================================-->

<!-- %coordinateTypes -->
<!--
<annotation>
<documentation>
	<entityName>%coordinateTypes;</entityName>
	<entityDescription>
		Different astronomical coordinate systems.
		<br></br>
		See <seeTag>Coordinates</seeTag>.
	</entityDescription>
</documentation>
</annotation>
-->

<!ENTITY % coordinateTypes
	"(equatorial|ecliptic|galactic)"
>

<!--========================================================================-->

<!-- %deliveryTypes -->
<!--
<annotation>
<documentation>
	<entityName>%deliveryTypes;</entityName>
	<entityDescription>
		Different ways of delivering data to the end-user.
		<br></br>
		See <seeTag>ImageData</seeTag>.
	</entityDescription>
</documentation>
</annotation>
-->

<!ENTITY % deliveryTypes
	"(ftp|url|email|mail)"
>

<!--========================================================================-->

<!-- %deviceTypes -->
<!--
<annotation>
<documentation>
	<entityName>%deviceTypes;</entityName>
	<entityDescription>
		Types of RTML devices.
		<br></br>
		See <seeTag>Device</seeTag>.
	</entityDescription>
</documentation>
</annotation>
-->

<!ENTITY % deviceTypes
	"(camera|spectrograph|photometer|polarimeter|spectropolarimeter|weatherStation|autoguider|webCamera|skyMonitor|other)"
>

<!--========================================================================-->

<!-- %exposureTypes -->
<!--
<annotation>
<documentation>
	<entityName>%exposureTypes;</entityName>
	<entityDescription>
		Types of RTML exposure times.
		<br></br>
		See <seeTag>Exposure</seeTag>.
	</entityDescription>
</documentation>
</annotation>
-->

<!ENTITY % exposureTypes
	"(time|snr)"
>

<!--========================================================================-->

<!-- %filterTypes -->
<!--
<annotation>
<documentation>
	<entityName>%filterTypes;</entityName>
	<entityDescription>
		Different standardized astronomical filters.
		<br></br>
		See <seeTag>Filter</seeTag>.
	</entityDescription>
</documentation>
</annotation>
-->

<!ENTITY % filterTypes
	"(none|clear|open|violet|blue|green|yellow|orange|red|U|B|V|R|I|J|H|K|L|M|N|U-Johnson|B-Johnson|V-Johnson|R-Johnson|I-Johnson|J-Johnson|H-Johnson|K-Johnson|L-Johnson|M-Johnson|N-Johnson|R-Cousins|I-Cousins|u-Sloan|b-Sloan|g-Sloan|r-Sloan|i-Sloan|u-Stromgren|b-Stromgren|&beta;-Stromgren|r-Stromgren|other)"
>

<!--========================================================================-->

<!-- %fluxTypes -->
<!--
<annotation>
<documentation>
	<entityName>%fluxTypes;</entityName>
	<entityDescription>
		Different types of astrnomical fluxes.
		<br></br>
		See <seeTag>Flux</seeTag>.
	</entityDescription>
</documentation>
</annotation>
-->

<!ENTITY % fluxTypes
	"(continuum|line|F-lambda|F-nu|lambda*F-lambda|nu*F-nu)"
>

<!--========================================================================-->

<!-- %fluxUnits -->
<!--
<annotation>
<documentation>
	<entityName>%fluxUnits;</entityName>
	<entityDescription>
		Different units for astronomical fluxes.
		<br></br>
		See <seeTag>Flux</seeTag>.
	</entityDescription>
</documentation>
</annotation>
-->

<!ENTITY % fluxUnits
	"(U-mag|B-mag|V-mag|R-mag|I-mag|Jansky|Jaskies|Jy|Jys|milli-Jansky|mJy|mJys|ergs/cm2/s|ergs/cm2/s/A|ergs/cm2/s/Hz|ergs/cm2/s/micron|Watts/m2|other)"
>

<!--========================================================================-->

<!-- %headerTypes -->
<!--
<annotation>
<documentation>
	<entityName>%headerTypes;</entityName>
	<entityDescription>
		Choice of FITS header completeness.
		<br></br>
		See <seeTag>FITSHeader</seeTag>.
	</entityDescription>
</documentation>
</annotation>
-->

<!ENTITY % headerTypes
	"(minimum|standard|all)"
>

<!--========================================================================-->

<!-- %imageDataTypes -->
<!--
<annotation>
<documentation>
	<entityName>%imageDataTypes;</entityName>
	<entityDescription>
		Whether the Image Data is a describing raw or reduced images.
		<br></br>
		See <seeTag>ImageData</seeTag>.
	</entityDescription>
</documentation>
</annotation>
-->

<!ENTITY % imageDataTypes
	"(raw|reduced)"
>

<!--========================================================================-->

<!-- %imageFormats -->
<!--
<annotation>
<documentation>
	<entityName>%imageFormats;</entityName>
	<entityDescription>
		Different formats for image data.
		<br></br>
		See <seeTag>ImageData</seeTag>.
	</entityDescription>
</documentation>
</annotation>
-->

<!ENTITY % imageFormats
	"(FITS|FITS16|gif|jpg|JPEG)"
>

<!--========================================================================-->

<!-- %institutionTypes -->
<!--
<annotation>
<documentation>
	<entityName>%institutionTypes;</entityName>
	<entityDescription>
		Different types of institutions which provide or
		order astronomical data.
		<br></br>
		See <seeTag>Contact</seeTag> and <seeTag>Institution</seeTag>.
	</entityDescription>
</documentation>
</annotation>
-->

<!ENTITY % institutionTypes
	"(university|college|school|research|commercial|private|network|other)"
>

<!--========================================================================-->

<!-- %lengthUnits -->
<!--
<annotation>
<documentation>
	<entityName>%lengthUnits;</entityName>
	<entityDescription>
		Different astronomical length units.
	</entityDescription>
</documentation>
</annotation>
-->

<!ENTITY % lengthUnits
	"(m|meter|meters|cm|centimeter|centimeters|km|kilometer|kilometers|mm|millimeter|millimeters|micron|microns|nm|nanometer|nanometers|Angstrom|Angstroms|ft|foot|feet|inch|inches|AU|A.U.)"
>

<!--========================================================================-->

<!-- %objectListTypes -->
<!--
<annotation>
<documentation>
        <entityName>%objectListTypes;</entityName>
	<entityDescription>
	        The types of object list that can be returned.
	</entityDescription>
</documentation>
</annotation>
-->

<!ENTITY % objectListType
        "(cluster|tagged)"
>

<!--========================================================================-->

<!-- %rtmlDocumentModes -->
<!--
<annotation>
<documentation>
	<entityName>%rtmlDocumentModes;</entityName>
	<entityDescription>
		The modes for RTML 2.0 documents.
		<br></br>
		See <seeTag>RTML</seeTag>.
	</entityDescription>
</documentation>
</annotation>
-->

<!ENTITY % rtmlDocumentModes
	"(score|request|confirmation|information|update|observation)"
>

<!--========================================================================-->

<!-- %simpleSkyTypes -->
<!--
<annotation>
<documentation>
	<entityName>%simpleSkyTypes;</entityName>
	<entityDescription>
		Simple descriptions of how bright the sky is.
		<br></br>
		See <seeTag>SkyConstraint</seeTag>.
	</entityDescription>
</documentation>
</annotation>
-->

<!ENTITY % simpleSkyTypes
	"(dark|gray|grey|bright)"
>

<!--========================================================================-->

<!-- %spectralRegions -->
<!--
<annotation>
<documentation>
	<entityName>%spectralRegions;</entityName>
	<entityDescription>
		Different names for spectral regions.
		<br></br>
		See <seeTag>Device</seeTag>,
		and
		<seeTag>Databank</seeTag>
	</entityDescription>
</documentation>
</annotation>
-->

<!ENTITY % spectralRegions
	"(radio|millimeter|infrared|optical|ultraviolet|x-ray|gamma-ray|other)"
>

<!--========================================================================-->

<!-- %statusTypes -->
<!--
<annotation>
<documentation>
	<entityName>%statusTypes;</entityName>
	<entityDescription>
		Status messages, mostly used in <seeTag>Observation</seeTag>
		elements.  See the documentation for
		<seeTag>Observation</seeTag> for a detailed description.
	</entityDescription>
</documentation>
</annotation>
-->

<!ENTITY % statusTypes
	"(ok|error|pending|incomplete|done|finished|aborted)"
>

<!--========================================================================-->

<!-- %timeUnits -->
<!--
<annotation>
<documentation>
	<entityName>%timeUnits;</entityName>
	<entityDescription>
		Units for astronomical times, including their abbreviations.
		<br></br>
		See <seeEntity>calendarUnits<seeEntity> and
		<seeEntity>timeSystemUnits<seeEntity>.
	</entityDescription>
</documentation>
</annotation>
-->

<!ENTITY % timeUnits
	"(s|sec|secs|second|seconds|ms|msec|msecs|millisecond|milliseconds|microsec|microsecs|microsecond|microseconds|min|mins|minutes|hr|hrs|hour|hours|%calendarUnits;|%timeSystemUnits;)"
>

<!--========================================================================-->

<!-- %trackRateTypes -->
<!--
<annotation>
<documentation>
	<entityName>%trackRateTypes;</entityName>
	<entityDescription>
		Different types of telescope track rates.
		<br></br>
		See <seeTag>Target</seeTag>.
	</entityDescription>
</documentation>
</annotation>
-->

<!ENTITY % trackRateTypes
	"(siderial|off|lunar|Mercury|Venus|Mars|Jupiter|Saturn|Uranus|Neptune|Pluto|custom|manual)"
>

<!--========================================================================-->

<!-- %typeSystemUnits -->
<!--
<annotation>
<documentation>
	<entityName>%timeSystemUnits;</entityName>
	<entityDescription>
		Astronomical time systems.
		<br></br>
		See <seeEntity>timeUnits</seeEntity>.
	</entityDescription>
</documentation>
</annotation>
-->

<!ENTITY % timeSystemUnits
	"(HJD|JD|BJD|MJD)"
>

<!--========================================================================-->

<!-- %velocityTypes -->
<!--
<annotation>
<documentation>
	<entityName>%velocityTypes;</entityName>
	<entityDescription>
		Types of velocities.
		<br></br>
		See <seeTag>RadialVelocity</seeTag>.
	</entityDescription>
</documentation>
</annotation>
-->

<!ENTITY % velocityTypes
	"(heliocentric|barycentric|LSR|other)"
>
<!--========================================================================-->

<!-- %velocityUnits -->
<!--
<annotation>
<documentation>
	<entityName>%velocityUnits;</entityName>
	<entityDescription>
		Units for velocities.
		<br></br>
		See <seeTag>RadialVelocity</seeTag>.
	</entityDescription>
</documentation>
</annotation>
-->

<!ENTITY % velocityUnits
	"(km/s|z)"
>
