When.com Web Search

Search results

  1. Results From The WOW.Com Content Network
  2. Apparent magnitude - Wikipedia

    en.wikipedia.org/wiki/Apparent_magnitude

    closest star (other than the Sun) +11.8 moon Phobos: seen from Earth Maximum brightness; brighter moon of Mars +12.23 star R136a1: seen from Earth Most luminous and massive star known [65] +12.89 moon Deimos: seen from Earth Maximum brightness +12.91: quasar 3C 273: seen from Earth brightest (luminosity distance of 2.4 billion light-years) +13. ...

  3. Luminosity - Wikipedia

    en.wikipedia.org/wiki/Luminosity

    A star also radiates neutrinos, which carry off some energy (about 2% in the case of the Sun), contributing to the star's total luminosity. [5] The IAU has defined a nominal solar luminosity of 3.828 × 10 26 W to promote publication of consistent and comparable values in units of the solar luminosity. [6]

  4. Absolute magnitude - Wikipedia

    en.wikipedia.org/wiki/Absolute_magnitude

    L ★ is the star's luminosity (bolometric luminosity) in watts; L 0 is the zero point luminosity 3.0128 × 10 28 W; M bol is the bolometric magnitude of the star; The new IAU absolute magnitude scale permanently disconnects the scale from the variable Sun.

  5. Magnitude (astronomy) - Wikipedia

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

    An illustration of light sources from magnitude 1 to 3.5, in 0.5 increments. In astronomy, magnitude is a measure of the brightness of an object, usually in a defined passband.

  6. Orders of magnitude (illuminance) - Wikipedia

    en.wikipedia.org/wiki/Orders_of_magnitude...

    Cloudy night sky without moon [4] 400 μcd/m 2 "Darkest sky" [5] 1 mcd/m 2: Night sky [6] 1.4 mcd/m 2: Typical photographic scene lit by full moon [7] 10 −2: 5 mcd/m 2: Approximate scotopic/mesopic threshold [8] 10 −1: 10 0: cd/m 2: 2 cd/m 2: Floodlit buildings, monuments, and fountains [9] 10 1: 5 cd/m 2: Approximate mesopic/photopic ...

  7. Astronomical spectroscopy - Wikipedia

    en.wikipedia.org/wiki/Astronomical_spectroscopy

    The Star-Spectroscope of the Lick Observatory in 1898. Designed by James Keeler and constructed by John Brashear.. Astronomical spectroscopy is the study of astronomy using the techniques of spectroscopy to measure the spectrum of electromagnetic radiation, including visible light, ultraviolet, X-ray, infrared and radio waves that radiate from stars and other celestial objects.

  8. Photographic magnitude - Wikipedia

    en.wikipedia.org/wiki/Photographic_magnitude

    Prior to photographic methods to determine magnitude, the brightness of celestial objects was determined by visual photometric methods.This was simply achieved with the human eye by compared the brightness of an astronomical object with other nearby objects of known or fixed magnitude: especially regarding stars, planets and other planetary objects in the Solar System, variable stars [1] and ...

  9. Star - Wikipedia

    en.wikipedia.org/wiki/Star

    It is a function of the star's luminosity, its distance from Earth, the extinction effect of interstellar dust and gas, and the altering of the star's light as it passes through Earth's atmosphere. Intrinsic or absolute magnitude is directly related to a star's luminosity, and is the apparent magnitude a star would be if the distance between ...