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  2. Apparent magnitude - Wikipedia

    en.wikipedia.org/wiki/Apparent_magnitude

    minimum brightness [42] −1.47: star system Sirius: seen from Earth Brightest star except for the Sun at visible wavelengths [45] −0.83: star Eta Carinae: seen from Earth apparent brightness as a supernova impostor in April 1843 −0.72: star Canopus: seen from Earth 2nd brightest star in night sky [46] −0.55: planet Saturn: seen from Earth

  3. Magnitude (astronomy) - Wikipedia

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

    [8] [9] Every interval of one magnitude equates to a variation in brightness of 5 √ 100 or roughly 2.512 times. 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.

  4. Bortle scale - Wikipedia

    en.wikipedia.org/wiki/Bortle_scale

    The Bortle dark-sky scale (usually referred to as simply the Bortle scale) is a nine-level numeric scale that measures the night sky's brightness of a particular location. It quantifies the astronomical observability of celestial objects and the interference caused by light pollution .

  5. Sky quality meter - Wikipedia

    en.wikipedia.org/wiki/Sky_Quality_Meter

    Sky Quality Meter model SQM-L. A sky quality meter (SQM) is an instrument used to measure the luminance of the night sky, more specifically the Night Sky Brightness (NSB) at the zenith, with a bandwidth ranging from 390 nm to 600 nm. [1]

  6. Astrometry - Wikipedia

    en.wikipedia.org/wiki/Astrometry

    In doing so, he also developed the brightness scale still in use today. [1] Hipparchus compiled a catalogue with at least 850 stars and their positions. [ 2 ] Hipparchus's successor, Ptolemy , included a catalogue of 1,022 stars in his work the Almagest , giving their location, coordinates, and brightness.

  7. Alpha Librae - Wikipedia

    en.wikipedia.org/wiki/Alpha_Librae

    The two brightest components of Alpha Librae form a double star moving together through space as common proper motion companions. They are separated in the sky by an angular distance of 231" (3'51"). The position angle of the companion is 314 degrees. The brighter of the two is a white star of spectral type A3, with an apparent magnitude of 2.8 ...

  8. Cosmic distance ladder - Wikipedia

    en.wikipedia.org/wiki/Cosmic_distance_ladder

    By measuring these properties from a star's spectrum, the position of a main sequence star on the H–R diagram can be determined, and thereby the star's absolute magnitude estimated. A comparison of this value with the apparent magnitude allows the approximate distance to be determined, after correcting for interstellar extinction of the ...

  9. Zeta Eridani - Wikipedia

    en.wikipedia.org/wiki/Zeta_Eridani

    ζ Eridani (Latinised to Zeta Eridani) is the binary star's Bayer designation.WDS J03158-0849 A is its designation in the Washington Double Star Catalog.The designations of the two components as WDS J03158-0849 Aa and Ab derive from the convention used by the Washington Multiplicity Catalog (WMC) for multiple star systems, and adopted by the International Astronomical Union (IAU).