List of astronomical databases
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  - 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  - A set of 110 astronomical objects catalogued by Charles Messier.
- New General Catalogue  - A set of 7,840 deep-sky objects compiled by John Louis Emil Dreyer.