After reading Jonathon's comments and re-reading the UCD vocabulary
document again, I realized that we definitely need a few changes:
instr.obsty.site.seeing
Does this mean we need...
instr.obsty.site.temperature instr.obsty.site.humidity Seem like a better solution would be to introduce "weather", whichpermits the concatenation
instr.obsty.site;weather.seeing
which would open a new handy family
weather | meteorological condition weather.seeing | atmospheric image quality weather.temp | local temperature weather.humidity | relative humidity weather.dewpoint | dewpoint temperature weather.precipitation | presence of rain/snow/sleet (boolean?) This would be VERY helpful for VOEvent/RTML. I won't open up a new discussion of the uneven choice of contractions (e.g. "temp" instead of "temperature" but "wavenumber" instead of "wavenum" - sigh!). The topic "space weather" comes into mind as well , but I'll let others worry about that.
2. instr
First of all, a trivial but needed addition:
instr.det.temp | temperature of detector
Next: we presently have "instr.tel.focus" and "instr.fov" which are quantities which refer to the "end-users" - no info about how the fov or focus came into being. The problem is whether to assign something like "focus" to the telescope or to the instrument. Generally, the fov of an instrument (e.g. CCD camera) is very different from that of the telescope. Do we then interpret "instr" things as being from a black box or from a specific instrument hanging on a telescope? If it's the latter, then one may need double entries. In any case there's a need for something like instr.tel.aperture | geometric diameter of telescope optics instr.tel.area | (effective?) collecting area of telescope optics instr.tel.focallength | focal length (effective?) of telescope instr.tel.fRatio | ratio of focal length to aperture diameter instr.tel.temp | temperature of telescope After all, we already have instr.focus, which is a much less needed number than the above! Sounds to me as if we need to distinguish between generic instr = e.g. telescope+filterwheel+CCD or telescope+spectrograph+CCD and "device" (can't think of a better name) which could be just the instrument part of the above (e.g. just the imaging camera or just the spectrograph). This would also imply that we need to make tel a primary key, since the telescope doesn't "belong" to the generic instrument - it's an associated thing. This would solve Jonathon's suggested of using obs.image;obs.calib;instr.det.flat;instr.tel.dome (i.e. using proposed UCDs obs.calib and instr.tel.dome) by permitting obs.image;obs.calib;inst.det.flat;tel.dome and would permit the differentiation between e.g. instr.focallength and tel.focallength. On the other hand, this means a lot of double entries which could only be gotten rid of using something like instr;optics.focallength tel;optics.focallength (unfortunately, "opt" is already taken: if we would be using "optical" for wavelength band and "optics" for optics, there wouldn't be anyconfusion).
In summary, we need to get rid of
instr.tel instr.tel.focus and add optics optics.focus optics.focallength optics.aperture optics.area optics.fRatio tel tel.dome (instr.obsty.dome is no good if there are lots of domes at the site) tel.mount (e.g. "alt-az", "equatorial", "english",....)
3. PLEASE PLEASE PLEASE change
src.class.struct -> src.class.struct.BautzMorgan src.class.distance -> src.class.distance.Abell src.class.richness -> src.class.richness.Abell src.spType -> src.class.spectral.MK src.morph.type -> src.morph.Hubble The present definitions associating general class descriptions with very particular versions of mostly extragalactic classifications are absolutely insane! Or, the description has to be changed to something like src.class.struct | structure classification, e.g. Bautz-Morgan galaxy type src.class.distance | distance classification, e.g. Abell galaxy cluster src.class.richness | richness classification, e.g. Abell galaxy cluster src.class.spectral | spectral classification, e.g. MK spectral class which results in a loss of specificity. There are other spectral classes beyond MK stellar, other richness classifications other than Abell (e.g. open stellarclusters), ....
Rick
Dr. Frederic V. Hessman Hessman-at-Astro.physik.Uni-Goettingen.DE Universitaets-Sternwarte Tel. +49-551-39-5052 Geismarlandstr. 11 Fax +49-551-39-5043 37083 Goettingen http://www.uni-sw.gwdg.de/~hessman
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http://monet.uni-goettingen.deReceived on 2005-06-10Z12:09:17
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