Category:Astronomical objects by year of discovery

Subcategories named "Astronomical objects discovered in " should be sorted by discovery year, month, and day. Please use the sortkey  if all are known. Otherwise, use  for unknown day, and   for unknown month and day. Astronomical objects discovered by (before 1500) should be sorted similarly, but omitting the century. For instance, the supernova of 1054 AD would be sorted as  as it was discovered on July 4, (10)54. Use this search to find all pages in these subcategories that are still missing a sortkey.