Canis Major
Canis Major contains Sirius, the brightest star in the night sky, known as the "dog star". It is bright because of its proximity to the Solar System. In contrast, the other bright stars of the constellation are stars of great distance and high luminosity. At magnitude 1.5, Epsilon Canis Majoris (Adhara) is the second-brightest star of the constellation and the brightest source of extreme ultraviolet radiation in the night sky. Next in brightness are the yellow-white supergiant Delta (Wezen) at 1.8, the blue-white giant Beta (Mirzam) at 2.0, blue-white supergiants Eta (Aludra) at 2.4 and Omicron at 3.0, and white spectroscopic binary Zeta (Furud), also at 3.0. The red hypergiant VY Canis Majoris is one of the largest stars known, while the neutron star RX J0720.4-3125 has a radius of a mere 5 km.
List of extremes in the sky
The greatest concentration of bright stars is around Orion. Within a circle of 60 degrees radius around a point in Monoceros at RA 6:30, DE 5ºS, 11 stars of magnitude +1.6 or brighter occur: Capella, Pollux, Castor, Regulus, Procyon, Sirius, Adhara, Canopus, Rigel, Betelgeuse and Aldebaran. No other part of the sky consists of so many bright stars. The entire sky consists of 23 such stars.
Narrowing the circle to 50 degrees and moving the center to the midway point of Capella and Canopus (a few degrees east of Orion's belt) will still consist of 9 stars leaving out only Regulus.