The Object Upload tools (cross-ID and Speclist) lets you search the SDSS database to find objects that match objects in your own list. If you have a list of stars or galaxies from another survey, you can use this tool to find the same objects in SDSS data. You can then use the Object Explorer to see what the SDSS has learned about your objects. Cross-ID finds SDSS data based on position, and Speclist finds SDSS photometric data based on SDSS plate/fiber number.
The cross-ID tool works by searching the SDSS database for objects near the positions you specify in your list. You can enter your list in the large window, or you can upload the list as a text file. The list can have any of four formats, each of which is described on the Cross-ID page. You can have the tool return only the object nearest the position you specify (which will probably be the object you are interested in), or all objects within a specified radius. You can tell the tool what attributes to return for each SDSS object by selecting from the drop-down menu. You can have the tool return the results as an HTML table, as an XML (eXtended Markup Language) file, or as a CSV (Comma Separated Value) file.
Speclist works just like cross-ID, except that you should enter SDSS plate/MJD/fiber numbers instead of ra/dec. You can also enter a query in the query window that searches the SDSS data based based on your uploaded information. You can use the query window to specify what columns you want the Speclist tool to return.