Quote:
Originally Posted by renormalised
And to add to what Rob has posted there, the difference between the 5" refractor and the 10" dob is a factor of 4 in the light gathering capability, so that the 10" will collect 4 times the light of the 5". Not surprisingly, the difference between a mag 13.1 and a mag 14.7 star is approximately 4 times the amount of light (4.3 to be more exact....2.512^1.6).
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Hi Carl,
I like that approach.
For those unfamiliar with the number 2.512 (Pogson's ratio).
A magnitude 1 star is 100 times as bright as a magnitude 6 star.
This is a magnitude difference of 6-1=5.
The 5th root of 100 is approximately 2.512 or 2.512^5=100.
Thus, a magnitude 1 star is 2.512 times as bright as a magnitude 2 star, a magnitude 2 star is 2.512 times as bright as a magnitude 3 star and so on.
Regards, Rob