
Arcturus (α Boo, α Boötis, Alpha Boötis) of the constellation Boötes is the brightest star in the northern celestial hemisphere. With a visual magnitude of −0.04, it is the fourth brightest star in the night sky, after −1.46 magnitude Sirius, −0.86 magnitude Canopus, and −0.27 magnitude Alpha Centauri. It is a relatively close star at only 36.7 light-years from Earth, and, together with Vega and Sirius, one of the most luminous stars in the Sun’s neighborhood.
Arcturus is a type K1.5 IIIpe orange giant star, with an absolute magnitude of −0.30. It has likely exhausted its hydrogen from the core and is currently in its active hydrogen shell burning phase. It will continue to expand before entering horizontal branch stage of its life cycle.
Imaging telescopes or lenses: 127 ED doublet f/9 (homemade)
Imaging cameras: Homemade Planet 640×480 Color
Mounts: Konus EQ3.2
Software: Star Tools, Corel Paint Shop Pro x2, Emil Kraaikamp’s AutoStakkert!
Dates: July 2, 2012
Frames: 3×40″
Author: Giuseppe Donatiello
AstroPhotography of the day by SPONLI 10 June 2014