If you have astronomical imaging of the sky with celestial coordinates you do not know—or do not trust—then Astrometry.net is for you. Input an image and they’ll give you back astrometric calibration meta-data, plus lists of known objects falling inside the field of view.

They have built this astrometric calibration service to create correct, standards-compliant astrometric meta-data for every useful astronomical image ever taken, past and future, in any state of archival disarray. They hope this will help organize, annotate and make searchable all the world’s astronomical information.

http://astrometry.net/