I think Dave's wide common proper motion pair is an example of a community use case which won't be precomputed by LSST. A bit more tractable astrometric use case, might be to identify streams or moving groups in some (limited) region of the sky.
Sorry, it was 6 criteria for determining whether LSST delivers the data product. Using those criteria a parametrization of variability is almost certainly provided. By the way, in my ignorance, I don't understand why the wide pair problem is so hard. Sort on one element of PM, find pairs, check the other element. Is it the 200,000,000 element sort that kills one? I thought there were some pretty fancy sort algorithms these days. Kem > I hit the "d" key too quickly. Was a gross parameterization of > photometric > variability one of Ken's 6 enabling computations? > > With respect to how big we let the DM load get, are there ground rules > as to the sorts of queries that LSST will accept? Wearing my Pan-STARRS > hat, I tried to break SAIC's implementation of Oracle's version of USNO-B > by giving it the wide physical pairs problem in SQL. The task is to see > if there are pairs of stars with similar proper motions but very widely > spaced on the sky (as differing from the normal common proper motion > problem where the stars are relatively close together on the sky). > Needless to say, Oracle never did finish looking for any star with > another star having the same motion but more than 150 degrees away. > Its default search was about as inefficient as one can imagine, and > N**2 searches where N is big can take a very long time. > > At what level of complexity does the server reject a query, and once > rejected, what is the path for the user to take into the LSST archive? > > -Dave > _______________________________________________ > LSST-data mailing list > [email protected] > http://www.lsstmail.org/mailman/listinfo/lsst-data > _______________________________________________ LSST-data mailing list [email protected] http://www.lsstmail.org/mailman/listinfo/lsst-data
