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  2. Magnitude (astronomy) - Wikipedia

    en.wikipedia.org/wiki/Magnitude_(astronomy)

    Consequently, a magnitude 1 star is about 2.5 times brighter than a magnitude 2 star, about 2.5 2 times brighter than a magnitude 3 star, about 2.5 3 times brighter than a magnitude 4 star, and so on. This is the modern magnitude system, which measures the brightness, not the apparent size, of stars.

  3. Apparent magnitude - Wikipedia

    en.wikipedia.org/wiki/Apparent_magnitude

    Combined magnitude (3rd brightest star in night sky) −0.04: star Arcturus: seen from Earth 4th brightest star to the naked eye [47] −0.01: star Alpha Centauri A: seen from Earth 4th brightest individual star visible telescopically in the night sky +0.03: star Vega: seen from Earth originally chosen as a definition of the zero point [48] +0. ...

  4. Absolute magnitude - Wikipedia

    en.wikipedia.org/wiki/Absolute_magnitude

    The Greek astronomer Hipparchus established a numerical scale to describe the brightness of each star appearing in the sky. The brightest stars in the sky were assigned an apparent magnitude m = 1, and the dimmest stars visible to the naked eye are assigned m = 6. [7] The difference between them corresponds to a factor of 100 in brightness.

  5. Your Stargazing Calendar for 2024: Catch a Total Solar ...

    www.aol.com/stargazing-calendar-2024-catch-total...

    One magnitude is defined as a ratio of brightness of 2.512 times. So a star of magnitude 5.0 is 2.512 times brighter than one of magnitude 6.0. A star that is magnitude 1.0 is then 100 times as ...

  6. List of brightest stars - Wikipedia

    en.wikipedia.org/wiki/List_of_brightest_stars

    Stellar brightness is based on the apparent visual magnitude as perceived by the human eye, from the brightest stars of 1st magnitude to the faintest at 6th magnitude. Since the invention of the optical telescope and the documenting of binary stars and multiple star systems, stellar brightness could be expressed as either individual (separate ...

  7. Luminosity - Wikipedia

    en.wikipedia.org/wiki/Luminosity

    The magnitude of a star, a unitless measure, is a logarithmic scale of observed visible brightness. The apparent magnitude is the observed visible brightness from Earth which depends on the distance of the object. The absolute magnitude is the apparent magnitude at a distance of 10 pc (3.1 × 10 17 m), therefore the bolometric absolute ...

  8. Bortle scale - Wikipedia

    en.wikipedia.org/wiki/Bortle_scale

    The scale ranges from Class 1, the darkest skies available on Earth, through to Class 9, inner-city skies. It gives several criteria for each level beyond naked-eye limiting magnitude (NELM). [1] The accuracy and utility of the scale have been questioned in 2014 research. [2] [why?] The table summarizes Bortle's descriptions of the classes. For ...

  9. First-magnitude star - Wikipedia

    en.wikipedia.org/wiki/First-magnitude_star

    First-magnitude stars are the brightest stars in the night sky, with apparent magnitudes lower (i.e. brighter) than +1.50. [1] [2] Hipparchus, in the 1st century BC, introduced the magnitude scale. He allocated the first magnitude to the 20 brightest stars and the sixth magnitude to the faintest stars visible to the naked eye.