View Single Post
  #14  
Old 22-04-2014, 01:01 PM
Wavytone
Registered User

Wavytone is offline
 
Join Date: Jul 2008
Location: Killara, Sydney
Posts: 4,147
Quote:
Originally Posted by noeyedeer View Post
mirror squared / by other mirror squared

8^ = 64 / 5.9^= 34.81

=1.84 times the light gathering, so 84% more light compared to the acro ..going from the 8" dob to your acro you lost nearly half of your light gathering power

or 100/64 = 1.56 if comparing the dobs...and 56% more light between the dobs
Hi matt, yes a 50% difference is noticeable visually, however the magnitude scale is logarithmic (as are our eyes, too) and you might like to look at difference in limiting magnitudes as well.

Put it another way - after using a big scope it can be a tad amusing to realise what you can actually see in a 8x50mm finder when you look closely in dark skies.
Reply With Quote