The first observer to catalog differences in star brightnesses was Greek astronomer Hipparchus. He created a catalog around 135 B.C.E. of roughly 850 stars divided into six ranges. He called the ...

Is a 6th-magnitude star 6 times brighter than a 1st-magnitude star? The "magnitude" scale used to express stellar brightness ...

You know that M31 (NGC 224) in Andromeda is another galaxy far outside our own Milky Way, don’t you? Of course you do! Everyone knows that. But we haven’t always known it. In fact, we’ve only known ...

The brightest planet as seen from Earth is Venus, which has an average V-band apparent magnitude of -4.14, making it the second-brightest object in the night sky after the Moon. Apparent and absolute ...