1. Sirius (Alpha Canis Majoris) Apparent Magnitude-1.44 Size (LY) 9
2. Canopus (Alpha Carinae) Apparent Magnitude-.62 Size (LY) 313
3. Arcturus (Alpha Bootis) Apparent Magnitude-0.05 Size (LY) 37
4. Rigel Kentaurus (Alpha Centauri) Apparent Magnitude-0.01 Size (LY) 4
Centaurus lies low in the sky and is impossible to see from most of the United States. It contains within it the closest star, other than the sun, to the solar system, Proxima Centauri. This is a companion star to Rigel Kentaurus, also known as Alpha Centaur, lying a mere 4.36 light years away. A modest telescope will split it as double. The brighter is a yellow class G dwarf star that, with a temperature of 5770 Kelvin (10 degrees cooler than solar), appears almost identical to the Sun. The companion, over a magnitude fainter, is a cooler (5300 Kelvin) class K star, the two making an obvious color contrast.
5. Vega ( Alpha Lyrae) Apparent Magnitude0.03 Size (LY) 25
Lyra is an ancient constellation easily seen high in the northern skies. It is visible in the summer and fall. Its close proximity makes it unusually bright-- 54 times the brightness of our sun. Vega is a classic white main sequence star. Because of its massive size, 2.5 times that of our sun, it uses its internal fuel faster and will burn out in less than a billion years.
6. Capella ( Alpha Aurigae) Apparent Magnitude0.08 Size (LY) 42
Auriga was one of the earliest constellations named and represented shepherding. The brightest star, Capella, meant she goat, and the stars below were thought of as kids. Capella is yellow-white and in the middle of the temperature range. It is the best known double star, both components of which are larger and brighter than the sun.
7. Rigel ( Beta Orionis) Apparent Magnitude0.18 Size (LY) 773
Orion is one of the oldest and most recognized constellations.Orion is large and easy to find. It contains many bright stars and in the belt are three very bright stars lined up in a row. Rigel represents Orion's foot. Although it is Orion's beta star, it is brighter than the alpha star Betelgeuse. It is a "blue supergiant," a fairly hot star with a surface temperature (11,000 Kelvin) about double that of our Sun.
8. Procyon ( Alpha Canis Minoris) Apparent Magnitude0.40 Size (LY) 11
Canis Minor is the smaller of the the two hunting dogs used by Orion. The constellation is one of the smallest in the sky and is composed primarily by only two bright stars, one of which is Procyon. A white class F subgiant-dwarf, Procyon radiates with the power of 6.9 Suns, having a surface temperature of 6530 Kelvin. Procyon has a faint companion star, Procyon B, was not actually seen until 1896, its existence was known as early as 1844 because of the star wobble it exserts on Procyon A.
9. Betelgeuse ( Alpha Orionis) Apparent Magnitude0.45 Size (LY) 522
The great star Betelgeuse is one of the two that dominate mighty Orion of northern winter, the other Rigel, the pair respectively called Alpha and Beta Orionis.
10. Achernar ( Alpha Eridani) Apparent Magnitude0.45 Size (LY) 144
Achernar is a bright blue star of six to eight solar masses . Although classified as a main sequence (dwarf) star, it is thousands of times brighter than the Sun . It is visible in the southern part of the night sky. It remains permanently below the horizon from many densely populated portions of Earth 's northern hemisphere. From those Southern hemisphere countries from which it can be seen best, it is particularly conspicuous through being highest in the night sky in November.
11. Hadar (Beta Centauri) Apparent Magnitude0.61 Size (LY) 526
Hadar, less often known as Agena (from the "knee" of the Centaur), is quite the magnificent star: rather, stars. Visually, Alpha Centauri is notably brighter than Hadar, but only because (ignoring Proxima) it is the closest star to the Earth. At a distance of 335 light years, Hadar, a blue class B (B1) giant, is 77 times farther away, and is bright because it is truly luminous.
12. Altair (Alpha Aquilae) Apparent Magnitude0.76 Size (LY) 17
Altair, the 13th brightest star in the sky and the Alpha star of Aquila the Eagle, is also the southern anchor of the famed Summer Triangle , which it makes with Vega and Deneb . The Arabic name "Altair," reflective of the constellation itself, comes from a phrase meaning "the flying eagle." Though the constellation does not look much like its name, Altair itself is flanked by a pair of stars (the Beta and Gamma stars Alshain and Tarazed ) that really do remind the sky- gazer of a bird with outstretched wings.
13. Acrux ( Alpha Crucis ) Apparent Magnitude0.77 Size (LY) 321
Crux (Southern Cross)
Among the most famous constellations in the sky is a "modern" one that is quite invisible from most of the populated northern hemisphere: Crux , the Southern Cross. Some 60 degrees below the celestial equator, Crux is well-visible only roughly south of the Tropic of Cancer (a good reason to go to Hawaii). From nearly all the temperate southern hemisphere, Crux is circumpolar (never setting).