Quote:
Originally Posted by Peter Ward
Yes it is.
BTW .....a half wave of spherical error spreads light in a totally different manner to a scope that is obstructed, but perfectly corrected.
..i.e actually reaches focus over it's entire field....as opposed to some clunker you can't actually focus anywhere in particular.
With obstructed systems, sure some MTF spatial frequencies may suffer, some may actually improve, but if well made, everything is *in focus*
(I frankly couldn't give a rats it the light is spilling into the first or even second diffraction ring...so long as that is the only place it's going)
Here is a link to a "roll-over" pair of images to illustrate the point.  |
Certainly a major difference, Peter. What refractor was used for the comparison?