Pogson ratio

British

/ ˈpɒdʒsən /

noun

the brightness ratio of two celestial objects that differ by one magnitude. On the Pogson scale a difference of 5 magnitudes is defined as a difference of 100 in the intensities of two stars; therefore a difference of 1 magnitude is equal to the fifth root of 100, i.e. 2.512

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Etymology

Origin of Pogson ratio

C19: named after N. R. Pogson (1829–91), British astronomer

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023