Astrophysics (index)

Magnitude

(a logarithmic measure of brightness)

Astronomical Magnitude is an indicator of the brightness of a star (or other astronomical body) based upon differentiation of brightness by eye, or as has been formalized, a logarithmic scale with lower numbers brighter, essentially -2.5 times the log 10 of the intensity. Some magnitudes:

  • -7 - Sun
  • -5 - Venus at maximum
  • -3 - Jupiter or Mars at maximum
  • -2 - Mercury at maximum
  • -1 - Sirius, the brightest star
  • 0 - Vega, Saturn at maximum
  • 32 - Visible Light limit of HST

Relative magnitude:

m(1)-m(2) = -2.5 log(10)( I(1)/I(2) )
  • I - intensity (watts per square meter)

Apparent Magnitude (m) is scaled so that the star, Vega, has a magnitude of 0. Absolute Magnitude (M) is the apparent magnitude a star would have at 10 Parsecs (pc).


(measure,brightness,logarithmic,EMR)
http://en.wikipedia.org/wiki/Magnitude_(astronomy)

Referenced by:
Absolute Magnitude (M)
AB System
AD Leonis (AD Leo)
APM Galaxy Survey (APMUKS)
Apparent Magnitude (m)
All Sky Automated Survey for SuperNovae (ASAS-SN)
Astronomical Catalog
Astronomical Survey
Bonner Durchmusterung Catalog (BD)
Beta Centauri
Bolometric Correction
Bolometric Magnitude (Mbol)
Color Index
Cataclysmic Variable Star (CV)
Dense Core Mass Function (DCMF)
Galaxy Main Sequence
Gas Fraction Estimation
Hipparchus
K Correction
KELT
Lalande 21185
Main Sequence Fitting
Morphological Catalogue Of Galaxies (MCG)
M-Type Star (M)
NGTS
Nova
Photometer
Photometry
PLATO
Poynting Vector (S)
Ross 154
Ross 248
Scholz's Star
Supernova (SN)
Spectral Line
SuperWASP (SWASP)
Synthetic Photometry
Transiting Exoplanet Survey Satellite (TESS)
Transiting Planet
2dF Galaxy Redshift Survey (2dFGRS)
UBV Photometric System
Vega
Vega System

index