Constellation Guide is an astronomy reference site dedicated to the 88 constellations recognized by the International Astronomical Union (IAU), and the stars, asterisms and deep sky objects visible within them. The website was started by an amateur astronomer for personal reference in 2011. Over the years, it has grown into one of the more comprehensive constellation resources on the web.
What we cover and why
Constellation Guide tries to occupy the middle ground between being a comprehensive constellation hub that is accessible to beginners and useful to hobbyists, and a curiosity-driven resource for anyone who has seen a Hubble image or simply looked up at the sky and wondered what exactly they were looking at.
The site covers each constellation in depth, including mythology and history, positional data, major stars, asterisms, and deep sky objects. The celestial objects (stars and deep sky objects) covered on the site range from those accessible to amateur observers with binoculars and small telescopes to more recent discoveries with Hubble, James Webb, and other space and ground-based telescopes.
Sources and accuracy
The data used in the articles is drawn from authoritative catalogues and databases, including Simbad, HIP (Hipparcos) and Gaia DR3, and verified against publications from astronomy agencies, associations and research centres, including NASA, ESA, the IAU, the Jet Propulsion Laboratory (JPL), and the National Optical-Infrared Astronomy Research Laboratory (NOIRLab).
Deep sky object data references the NGC, IC, Messier and Caldwell catalogues. Any observational notes reflect practical experience at the eyepiece and not just theoretical visibility limits. Pages are updated regularly as catalogue data is revised and new observational notes are added.
About the author
Constellation Guide is written and maintained by an amateur astronomer with over 16 years of observing experience. The observations referenced on the site have for the most part been made with 15×70 binoculars and a 150mm Dobsonian reflector under skies ranging from Bortle 3 rural sites to Bortle 8 cities. Where aperture recommendations are given for specific objects, they reflect a practical range rather than theoretical limits.
Have a correction, suggestion, or question? Use the Contact page to get in touch.