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 ...

When we observe the stars in the night sky, their brightness can be pretty dramatic, but the way astronomers measure ...

If someone asks you, “How bright is that star?” and your answer is “Pretty bright,” that isn’t very useful. And, of course, it’s worthless for any type of comparative research. So for centuries, ...