Quote:
Originally Posted by The Mekon
It is a misconception that it is a misconception that a refractor is better at splitting doubles.
They are!!!
After using a Astro-Physics 130EDT for 22 years mostly on doubles, and now using an 18" SDM with a fine mirror, I find that the refractor was way better.
With the 130 I could usually tell at a magnification of 115x whether a star was double or not. Increasing the magnification gave better view and would confirm the split. The 18" can do all that the refractor can BUT requires far more cool down time and much more sensitive to poor seeing conditions. I find I'm using a 7" off axis mask to get that clean look the refractor used to give.
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But if you are trying to split some 15th magnitude double star, your 18" will be vastly superior.
Like you, I made an aperture mask for my 14.5" dob, but with 4",5" and 6" holes - as I cut them out, I stuck velcro on them so as to use them as covers for the holes not in use. I don't use it often, but it did come in useful a couple of times with miserable seeing.
Cheers,
Renato