Chuck Norcutt wrote:
> For visual use alone a small telescope only needs a well illuminated image
> circle of about 1" (25mm) diameter. For 35mm size images one needs an image
> circle larger than that which requires a larger secondary
> mirror. The larger secondary blocks light transmission and reduces contrast
> through additional diffraction. One needs to make a good compromise in the
> design.
>
The Meade appears to do pretty well. There are a short baffle/hood glued
to the back of corrector plate, around the silvering, and a long, thin
one projecting forward from the center of the mirror toward the
secondary mirror. Those should reduce light spilling around and help
contrast.
Fortunately, contrast isn't the issue for me today that it was, as it
can easily be brought back up in post. It's always low in shots through
long distances of air, anyway, from water, dust, other pollution and
thermal movement, so I find it hard to say what the contribution of the
lens is.
Moose
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