Canis Major Constellation
Canis Major (The Greater Dog)
Canis Major, or "The Greater Dog," is a prominent constellation in the southern sky. It is most famous for containing Sirius, the brightest star in the night sky, which is often referred to as the "Dog Star." This constellation is part of the celestial depiction of Orion the Hunter, representing one of his hunting dogs.
Key Features
- Bright Stars: Canis Major is home to several bright stars, including:
- Sirius: The brightest star in the night sky, located about 8.6 light-years away. Its name means "glowing" or "scorching" in Greek.
- Adhara: The second-brightest star in the constellation, a luminous blue giant located about 430 light-years away.
- Wezen: A yellow-white supergiant star, marking the dog’s hindquarters.
- Mirzam: A blue-white giant star near Sirius, often called the "Announcer" because it rises just before Sirius.
- Deep-Sky Objects: Canis Major contains a few notable objects:
- Messier 41 (M41): An open star cluster located about 2,300 light-years away, visible to the naked eye under dark skies.
- NGC 2359 (Thor’s Helmet): A striking emission nebula shaped like a Viking helmet.
Mythological Background
In Greek mythology, Canis Major is often identified as one of Orion the Hunter’s faithful dogs. It accompanies Orion across the sky, assisting in his celestial hunts. Sirius, the brightest star in the constellation, is sometimes associated with the blazing heat of midsummer in ancient lore, leading to the term "Dog Days of Summer."
Other cultures also revered Canis Major. For example, in ancient Egyptian mythology, Sirius was linked to the goddess Isis and was a herald of the annual flooding of the Nile, a critical event for agriculture and survival.
Cultural Significance
Canis Major’s association with Sirius has made it a constellation of great historical and navigational importance. Sailors used Sirius as a guide due to its brightness and position near the celestial equator, making it visible from most parts of the world.
The constellation also plays a role in various cultural traditions and stories, often symbolizing loyalty, protection, and guidance. Its prominent stars and deep-sky objects make it a favorite for stargazers and astronomers alike.
Canis Major Rise and Set Timetable
| Time | Elevation | |
| Canis Major Transit | 16:57 | 27° |
| Moon Rise, 93.2% illuminated | 17:59 | 25° |
| Sunset | 20:33 | 9° |
| Civil sunset | 21:05 | 5° |
| Canis Major Set | 21:33 | |
| Astrosession begin | 21:42 | -1° |
| Moon Set | 05:05 | -73° |
| Astrosession end | 05:14 | -73° |
| Canis Major Rise | 12:18 |
Track Canis Major Position Throughout the Night
← Sat, 10 May 2025 →
| Time | |
| Altitude | |
| Azimuth |
Annual motion of Canis Major
| Date | Sat, 10 May 2025 |
| Twighlight start | 22:18 |
| Twighlight end | 04:28 |
| Twighlight duration | 6h 10m |
| Rise | 12:18 |
| Set | 21:29 |
| Elevation at transit | 27° |
| Transit time | 16:53 |
| Equatorial coordinates | RA: 06h 37m 20s", Dec: -23° 04' 40s |
| Magnitude | - |
| Constellation |
The graph is structured with the vertical axis showing the hours of the day, ranging from 12 AM to 12 AM the next day, while the horizontal axis spans each day of the year.
The reddish shaded area indicates the periods when the Canis Major is above the horizon, visible to observers. The white line marks the times when the celestial object reaches its highest point in the sky each day, known as the transit.
Acknowledgements
We gratefully acknowledge the International Astronomical Union (IAU) for defining and standardizing the official constellation boundaries, which provide a consistent framework for celestial mapping.
Special thanks to Sky & Telescope Magazine and contributors Roger Sinnott and Rick Fienberg for their collaboration in producing the charts and tables. The constellation patterns, drawn by Alan MacRobert, were influenced by the work of H. A. Rey and thoughtfully adjusted to align with earlier traditions.