Convert apparent and absolute magnitude

Calculator for the apparent and absolute brightness of stars and other bright celestial bodies in magnitudes (mag). Apparent magnitude is what we see or perceive with measurements. The absolute magnitude would be that which the celestial body would have at a distance of 10 parallax seconds or parsecs (about 32.6 light years). So the absolute brightness says something about the real dimension.
Brightness is given in magnitudes (mag), the lower the value, the brighter. The scale is logarithmic, the Sun as the brightest object in the sky has an apparent magnitude of −26.74 mag, the planet Neptune is at +7.67 mag already below the perception threshold of the naked eye.
The absolute brightness can be calculated from the apparent brightness and distance. The formula is M = -5 * lg( r / 10pc ) + m with apparent magnitude m, absolute magnitude M, distance r and the common logarithm lg. Please enter the distance and one of the two brightnesses to calculate the other brightness.

Apparent brightness:mag
Distance r:
Absolute brightness:mag

The units of distance are: m = meters, km = kilometers, mi = miles, AU = astronomical units, ly = light-years, pc = parsec

Examples: the Sun at a distance of 1 AU has an absolute magnitude of 4.82 mag. The star Deneb has an apparent magnitude of 1.25 and at a distance of 1550 light years an absolute magnitude of -7.13.

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