Quote:
Originally Posted by alistairsam
Hi,
what would the difference be visually when using the same eyepiece, say 25mm between an F4 scope and an F6 scope?
would the object be slightly bigger in an F6, but will there be a difference in brightness in an F4 as its a faster scope?
do faster scopes gather more light? i don't really understand how it makes such a difference in astrophotography as it reduces required exposure time dramatically.
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Assuming the same aperture and eyepiece, you'll get a lower magnification and wider field of view with the F/4. If it's a newt, you'll also be seeing coma at the edges of the FOV that won't be even remotely as obvious in the F/6. Faster scopes don't gather more light than slower ones, that is entirely a function of the aperture.