List of astronomical databases

NGC-4676 or Mice galaxies.

This is a list of astronomical databases. According to ESA, the number of galaxies in the observable universe is 2×10¹² (two trillion) and as many as 1×10²⁴ stars (more stars than all the grains of sand on planet Earth).

• Guide Star Catalog [1] - GSC-I contains 19 million stars with apparent magnitudes of 6 to 15. GSC-II is an all-sky catalog of 2 billion stars and galaxies.
• Messier Catalogue [2] - A set of 110 astronomical objects catalogued by Charles Messier.
• New General Catalogue [3] - A set of 7,840 deep-sky objects compiled by John Louis Emil Dreyer.