Quote:
Originally Posted by Sean
To determine whether an object is likely to be visible compare your current sky glow to the surface brightness. An average observer might see an object down to 3 magnitudes fainter than the skyglow. So for M33 you would probably need a sky darkness around 20.5
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Wait, now im confused again. How can you see an object that has a SB 3 magnitudes *fainter than the surrounding skyglow? The other way round I could understand; needing the surface brightness of the object to be at least 3 magnitudes *brighter than the background skyglow in order to have enough contrast for it to be visible, but *fainter? I must be missing something.
Cheers, Markus