Apparent magnitude is a measure of the brightness of a celestial object as seen from Earth.
The lower the number, the brighter the object. Negative numbers indicate extreme brightness. We can see objects up to 6th magnitude without a telescope. Apparent magnitude is abbreviated m. This system of rating the brightness of celestial objects was developed by the Greek astronomer Hipparchus in 120 B.C. Absolute magnitude is a measure of the inherent brightness of a celestial object.