Quote:
Originally Posted by raymo
Yes, I realise that Rahim, but it rather defeats the purpose of having 102mm of aperture, might as well buy a 60 or 80mm f/10 or 12 in the first place.
raymo
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Yes
But i understand in cheap scopes, we can use all of aperture
just for low power (DSO) not for high power (lunar and planets)
In high power, outer part of aperture is useless.
Now i have SW200P and now i use 140mm stop down for high power.
Of course in reflectors, there is no CA but shape of mirror is not
ideal, and it is better to eliminate outer part of aperture.
I think just in high price scopes (near ideal optic) you can
use all of aperture in any situation (high and low power)