okm

This is an old topic, but I did want to correct this in case others are reading as well. 46mm obstruction for the Mak is not 38% - you need to look at the obstructed area, not the diameter. The obstruction is about 1662 mm^2, resulting in the unobstructed area being about 9645 mm^2. That's equivalent to about a 111 mm aperture. So the Mak should still have a more light coming through the lens. It's still more complicated than that because there is some loss from the primary and secondary mirrors.