Telescopes in XML part 2

Several weeks ago I mentioned my motivation for a simple telescope XML file and then I came up with a suggested format. Other things got in the way so I haven't really done a lot on this since. However, now seems a suitable time to push this forwards.

I've altered things slightly, taking into account some of the previous suggestions. Below is a table of tags with allowable values. Dave P suggested changing the <coordinates> tag in order to split the latitude and longitude up and provide future proofing for telescope not on the Earth. However, I would prefer to stick with the simple format that Google Earth uses rather than something all-singing and all-dancing like they use for the Virtual Observatory.

e.g. <name>42ft</name>
descStringA short description of the telescope. Limited number of characters?
e.g. <desc>The 42ft telescope at Jodrell Bank Observatory</desc>
linkURLLink to a web page with more information about the telescope.
e.g. <link>http://www.blah/42ft.html</link>
imageURLAn image showing the telescope. In jpg, gif or png formats.
e.g. <image>http://www.blah/42.png</image>
PointThe latitude/longitude of the telescope. Should be provided where possible, although for some it makes little sense e.g. Hubble.
Point -> coordinatesCoordinatesSame format as used by Google Earth i.e. latitude,longitude. Longitude ranges from 0 to 360 degrees. Latitude ranges from -90 to +90 degrees. A sign should be provided for latitude to avoid confusion. Optional but strongly recommended.
e.g. <coordinates>53.235864,-2.306592</coordinates>
heightReal numberThis is the height above mean sea level in metres. For space-based telescopes this may be omitted. Optional but strongly recommended.
e.g. <height>213.1</height>
statusStringThis is an open format field to provide any status information.
e.g. <status>Cryogenic failure, motors stopped.</status>
time*ISO 8601 Date StringTime when the information is this file was valid.
e.g. <time>2007-10-14T12:00:00Z</time>
objectStringThis contains the name of the object. An optional type attribute should be taken from the astronomy journal keyword list. Multiple types can be included using";" or "--" as a separator so that it is consistent with journal papers.
e.g. <object type="pulsars: individual: PSR J0534+2200">The Crab Pulsar</object>
position A tag to hold the current coordinates of the observation. The amount of precision in the coordinates is left to the author of the file. This allows for 'fuzzy' positions to be given when required.
position -> raReal numberThis is the Right Ascension as a single number in decimal degrees. RA in hours, minutes and seconds can be easily calculated.
e.g. <ra>123.456</ra>
position -> decReal numberThis is the Declination as a single number. Dec in degrees, arcminutes and arcseconds can be easily calculated.
e.g. <dec>+45.678</dec>
position -> epochStringA standard epoch for the Ra/Dec coordinates such as: B1950, J2000 etc
e.g. <epoch>J2000</epoch>
position -> azReal numbersThis is the azimuthal position in decimal degrees (north = 0, east = 90). An optional attribute dem can give the demanded azimuth if it is different to the actual azimuth of the telescope e.g. <az dem="172.34">170.06</az>
position -> elReal numbersThis is the elevation of the telescope in decimal degrees (horizon = 0.0, zenith = 90.0). An optional attribute dem can give the demanded elevation if it is different to the actual elevation of the telescope.
e.g. <el dem="34.6">34.567</el>

* these are required tags

Finally, does anyone have any experience writing DTDs or XML Schema?

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Posted in astro blog by Stuart on Sunday 14th Oct 2007 (13:06 BST) | Permalink
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