On Thu, 20 Apr 2006, Roy Williams wrote:
> Who is writing VOTables with sexagesimal in them? Surely the best thing is to
> convert to decimal as soon as possible, and convert back to sexagesimal (if
> wanted) at the last possible moment before the human eyes see it.
Roy (et al)
I agree with you for newly created VOTables, but I suspect that for some time converted FITS tables will be encountered quite frequently. Unfortunately this is an issue with which the FITS community has failed to deal, and it is a serious one. If you look at the thousands of tables in the Vizier collection, for example, you will find a substantial number (perhaps 30%) have celestial coordinates not in decimal but in sexagesimal, and in an amazing variety of formats (with minutes and decimals or minutes and seconds, with colons or spaces as separators, etc).
A few years ago a few of us tried to draft a proposal for a better way of describing these in FITS tables, but we didn't get anywhere: the task was too hard and the timescale for changing the FITS Standard was dauntingly long).
So I can see that we ought to discourage the use of sexagesimals in VOTable, but I think Mark has a point in suggesting that there ought to be a standard way of dealing with them. The same is true in web forms where users have to enter coordinates: some require RA/DEC in decimals, some allow or require sexagesimals, and it often takes some time to work out whether they need colons or spaces, and whether the two values should be separated by spaces or commas. It's all rather a mess.
-- Clive Page Dept of Physics & Astronomy, University of Leicester, Tel +44 116 252 3551 Leicester, LE1 7RH, U.K. Fax +44 116 252 3311Received on 2006-04-21Z11:24:10