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, ...

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.

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 ...

What is the baseline for determining the magnitude scale of celestial objects? Why do brighter objects have negative numbers? Dean Treadway Knoxville, Tennessee The first observer to catalog ...

II.—APPARENT MAGNITUDES: (b) PHOTOGRAPHIC. WITH the application of photography to astronomy it was inevitable that attempts should be made to determine apparent magnitudes by photography. Visual ...