About Atlas of the Sky
Atlas of the Sky draws accurate, readable star maps of all 88 constellations, finder charts for the named stars and the Messier objects, and monthly charts of the night sky. Every chart is generated from open astronomical catalogs and is free to use.
How the maps are made
- Stars: the Yale Bright Star Catalogue, 5th revised edition (Hoffleit & Warren 1991), with 9,096 stars down to about magnitude 6.5, the limit of the naked eye. Star colors come from the B−V color index.
- Constellation boundaries: the official IAU boundaries drawn by Eugène Delporte in 1930, from the digital version by Davenhall & Leggett (1989) with corrections by Bill Gray (2007), converted from the 1875 coordinates in which they were defined to the J2000 coordinates of the star catalog.
- Constellation lines: the stick figures compiled by Marc van der Sluys (ConstellationLines, CC BY 4.0), which follow the figures in common use.
- Star names: the official list of the IAU Working Group on Star Names (WGSN).
- Messier objects and distances: Wikidata (CC0).
Charts use a stereographic projection centered on each constellation, with north up and east to the left, as the sky looks when you face it. Positions are for the standard epoch J2000; the slow drift of the sky (precession) since then is far smaller than the size of a star dot.
Who runs the site
Atlas of the Sky is made by Appsplosion GbR in Germany. Corrections and questions: appsplosion.help@gmail.com.