Apparent magnitude

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Term: Apparent magnitude

A measure of a star's observed brightness (opposed to absolute magnitude); symbol m. It depends on the star's intrinsic brightness, its distance from the observer, and the amount of interstellar absorption. The brightest star Sirius has an apparent magnitude of -1.46, while the weakest stars visible with the naked eye in the most favorable observation conditions have magnitudes of about +6.5. The stars of magnitudes less than +23 are measured by professional observatories, whereas those of magnitudes less than +30 by a telescope such as the Hubble Space Telescope.

Created 2023.04.16
Last Modified 2023.04.16
Contributed by Ryan McGranaghan