time range
Often we need to support catalog queries that would be valid for a range of times for a target that has a non zero proper motion. E.g. the same target maybe observed now or in 6 months. To reduce the amount of queries we may rather do a single query that covers two positions of a target at times t1/t2. This can be seen on the image below as we query for a circle covering both ends of the time varying positions:
While this means we may get more results than needed the difference will be relatively small considering the max pm is 10 arcsec/y and we can limit the time range to e.g. 1 year.