Abell 39
Abell 39 is a planetary nebula located approximately 3,800 light-years away in the northern constellation Hercules. It has an integrated apparent visual magnitude of 13.7… Read More »Abell 39
Zeta Herculis
The Keystone
The Keystone is an asterism formed by four relatively bright stars in the constellation Hercules: Pi, Eta, Zeta and Epsilon Herculis. The trapezoid-shaped pattern makes it easy for observers to identify the constellation and to find several well-known deep sky objects. On a clear night, the Keystone can be seen between the bright Vega, the brightest star in Lyra, and the stars of Corona Borealis, the Northern Crown. The asterism represents Hercules’ torso.
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