Saturnseeing reloaded

"Henry Spencer" schrieb im Newsbeitrag ...
In article ,
Volker Hetzer wrote:
Refractors are said to be superior mainly for the fact that they do not
have a secondary mirror obstruction like reflectors that reduce contrast
and and light throughput. So image *contrast* not resolution, is better
than for the same aperture in a reflector.

So, we can make better lenses than mirrors? (in terms of contrast
and losses)

No, the issue is not the quality of the optical elements, but the
compromises inherent in the usual way they are used. Any system with a
central obstruction will have reduced contrast and increased losses.
Ok. Understood.

Thanks a lot!
Volker