An Etymological Dictionary of Astronomy and Astrophysics

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فرهنگ ریشه‌شناختی اخترشناسی-اخترفیزیک

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Balmer decrement
  کاهه‌ی ِ بالمر  
kâhe-ye Bâlmer
Fr.: décrément de Balmer  

The intensity ratio among the couple of relatively adjacent → Balmer lines, for example Hα/Hβ and Hβ/Hγ, which have well-known theoretical values. They are used to determine the → interstellar extinction.

See also: → Balmer; → decrement.