The astronomical magnitude system, initially developed by Hipparchus and refined by Ptolemy, quantifies the brightness of celestial objects, with brighter objects having lower magnitudes. Norman R.

Stars come in all colors and sizes. But our eyes limit us to seeing very few of those colors. And the range of apparent magnitudes of stars we can see with our naked eye is also rather limited.

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