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.

The initial magnitude scale was established by Greek astronomer Hipparchus around 135 B.C.E., categorizing approximately 850 stars into six ranges from 1st (brightest) to 6th (faintest) magnitude.

When we observe the stars in the night sky, their brightness can be pretty dramatic, but the way astronomers measure brightness is not how one might intuitively think about it. In astronomy, ...

I.—APPARENT MAGNITUDES: (a) VISUAL.THE magnitude of a star, as determined by direct astronomical observation, is a measure of its apparent brightness on a scale which has been precisely defined only ...