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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

    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

  4. List of brightest stars - Wikipedia

    en.wikipedia.org/wiki/List_of_brightest_stars

    This is a list of stars arranged by their apparent magnitude – their brightness as observed from Earth. It includes all stars brighter than magnitude +2.50 in visible light, measured using a V-band filter in the UBV photometric system.

  5. Sky brightness - Wikipedia

    en.wikipedia.org/wiki/Sky_brightness

    (The S 10 unit is defined as the surface brightness of a star whose V-magnitude is 10 and whose light is smeared over one square degree, or 27.78 mag arcsec −2.) The total sky brightness in zenith is therefore ~220 S 10 or 21.9 mag/arcsec² in the V-band. Note that the contributions from Airglow and Zodiacal light vary with the time of year ...

  6. 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]

  7. Photometry (astronomy) - Wikipedia

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

    A number of free computer programs are available for synthetic aperture photometry and PSF-fitting photometry. SExtractor [37] and Aperture Photometry Tool [38] are popular examples for aperture photometry. The former is geared towards reduction of large scale galaxy-survey data, and the latter has a graphical user interface (GUI) suitable for ...

  8. Personalize your background image, sounds, and toolbar ...

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    1. Sign in to Desktop Gold. 2. Click the Settings button. 3. Click Personalization. 4. Click the Sounds tab. 5. Click Customize My Sounds. 6. Search for a sound or select a category from the "All" menu at the top-right.

  9. First-magnitude star - Wikipedia

    en.wikipedia.org/wiki/First-magnitude_star

    In the 19th century, this ancient scale of apparent magnitude was logarithmically defined, so that a star of magnitude 1.00 is exactly 100 times as bright as one of 6.00. The scale was also extended to even brighter celestial bodies such as Sirius (-1.5), Venus (-4), the full Moon (-12.7), and the Sun (-26.7).