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 ...
Hanging below the easily recognized belt of Orion, M42 is often envisioned as part of the Hunter's sword. It is so large and bright - some 85' by 60' and magnitude 4.0 - that it is visible to the ...
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