wiki:magnitude

Differences

This shows you the differences between two versions of the page.

Link to this comparison view

wiki:magnitude [2023/11/11 21:32] – created Roy Proutywiki:magnitude [2023/11/11 21:32] (current) – removed Roy Prouty
Line 1: Line 1:
-The Greek astronomer Hipparchos is usually credited with the origin of the magnitude scale. He assigned the brightest stars he could see with his eye a magnitude of 1 and the faintest a magnitude of 6. However, in terms of the amount of energy received, a sixth magnitude star is not 6 times fainter than a first magnitude star, but more like 100 times fainter, due to the eye's non-linear response to light. This led the English astronomer Norman Pogson to formalize the magnitude system in 1856. He proposed that a sixth magnitude star should be precisely 100 times fainter than a first magnitude star, so that each magnitude corresponds to a change in brightness of 1001/5 = 2.512. For example, a star of magnitude 2 is 2.5121=2.512 times fainter than a star of magnitude 1, a star of magnitude 6 is 2.5122=6.3 times fainter than a star of magnitude 4, and a star of magnitude 25 is 2.5125=100 times fainter than a star of magnitude 20. Note how it is only the magnitude difference that determines the brightness ratio of two stars, not the absolute values of their magnitudes.+