Quote:
Originally Posted by Peter Ward
When was the last time you used a 20" scope?
Having first hand experience with an Alluna RC20 (no-AO) to my RC16 (AO) and even more so AP 305mm AO).....sorry... I disagree
Close...but it can't (OK I concede crappy optics to boot  ) Planewave CDK's are anything but.
There is enough BS here already. |
Dear Peter,
I have looked at Jupiter & Saturn through a
classical Cassegrain f/13.3 20" scope manufactured by Carl Zeiss at
the Auckland Observatory.
Amazing view but it wasn't twice as good as a Celestron C11 that was there outside the observatory.
Dawes limit tells me that a 12" telescope has 0.38 arc seconds of resolution.
A 20" scope has 0.23 arc seconds of resolution.
If you were trying to split a double star only one arc seconds apart -
in excellent one arc seconds seeing - the results would be the same -
neither scope could do it.
The larger scope has more light collecting power - so it goes deeper given the same time.
cheers
Allan