Multiple Object Search

Many use cases want to get back data for a list of objects which are scattered in the sky, either from a single catalogue or multiple catalogues.

• This could be thought of as a cross-match between two (or more) lists, constraining any one, two or more columns to be the same within a given tolerance - e.g. an automated version of the interactive crossmatching of various kinds available using TopCat. It is not practical to do it exactly like TopCat, however, if one or more of the catalogues to be searched are very large and cannot be loaded reasonably.
• Alternatively, a list of positions (or any property?) could be sent as a series of cone search or other queries to each catalogue (c.f. Vizier's Query by List).
• The user could specify a single tolerance/search radius, or there could be a default, but ideally the appropriate position (etc.) error would be automatically found from each catalogue.

-- AnitaRichards - 20 Apr 2006

A STILTS task along the lines of your second suggestion above would seem like a sensible, and tractable, way to approach this. It would dispatch a cone search for each row of an input table, collating all the result tables into a single output one. Obviously this will only be sensible for non-huge input tables. Should I try to come up with something like this?

-- MarkTaylor - 26 Apr 2006

Yes please Mark - this would be really useful!

-- JonathanTedds - 26 Apr 2006

Right ho. Watch this space.

-- MarkTaylor - 27 Apr 2006

I've implemented this as the new multicone task in STILTS release v1.2 (see http://www.starlink.ac.uk/stilts/). This dispatches a series of cone search queries to a given service URL, one for each row of a supplied table. This could be modified/extended to do e.g. SIAP queries as well, if required. Feedback welcome.

-- MarkTaylor - 07 Jul 2006