In article <[EMAIL PROTECTED]>, Jacek Becla <[EMAIL PROTECTED]> wrote:
> > - do either of the current prototype schemas (UW and sergei's) > > have time partitioning in mind? > > Sergei, Nicole and Russ, can you answer this? What is time partitioning? The UW database has a TAI field for each image. Object link to images, so it's easy to find the time at which a given object was measured. If integration time varies across the image (as is likely for LSST if a shutter is used, as somebody pointed out at a recent phone con), then: - Additional information is needed in the object table to allow computing time as a function of position on the image. - The time of each source should probably be computed as sources are detected, and stored as a separate TAI field in the source table. We have run into this issue ourselves. Time varies across the image for SDSS data (drift-scanned data). Our Image table has TAI and RowTime such that TAI of source = TAI of image + RowTime*CtrY. However, we have not yet added a TAI field to our Object table. -- Russell _______________________________________________ LSST-data mailing list [email protected] http://www.lsstmail.org/mailman/listinfo/lsst-data
