Quote:
Originally Posted by gregbradley
That is a good point. Its the strehl ratio at the eyepiece that should be quoted.
Another reason a good refractor can outperform its aperture compared to compound scopes.
However at a certain size compound scopes take the lead as a 10 inch APO is too big, heavy, long and expensive compared to say a 14 inch compound scope.
Where they meet is a point of debate but I estimate from my experience a good 7 inch APO will match or even surpass a 12.5 inch compound scope even an RC. The RC will get a bit more detail but not necessarily a more pleasing image and will take longer exposure to get there.
A 14.25 inch RC though I would say has a definite advantage over a 7 inch APO but is less versatile as reducers do not work on RC scopes with big chip cameras which nearly all new modern cameras are.
So with that in mind are you better off getting an ED120 or EON120 or the APO127 which I think are a similar proce tag compared to an 8 inch RC with unproven and most lilkely poor optics.
Are these RCs made in Taiwan? If they are I would have more confidence in them. Astrotech make really nice refractors.
Greg.
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All right I think I am up for this
. GSO do work out of Taiwan and produce some reasonable products and these RC's look the part if nothing else. Their effectiveness is yet to be seen but I am fairly confident that the optics will perform well enough for the price.
I often read threads that bash CATS due to their central obstruction with arguments based around loss of contrast. Yes contrast is lost but to suggest that you will need roughly double the aperture to achieve comparative results..... well hmmmm. The refractors have an advantage on planets with their higher contrast but lose out with their wide fields and in any case there are only 3 planets worth looking at in my book. The best pics of DSO's are mostly but not exclusively the products of CATS and there are far more than 3 of these
. You just cant beat the brute force of a big mirror and these can be held on target when using refractors as guide scopes which in my book is their best use.
[Rant finished]
Ciao Mark