filters and eyepieces
Posted 28 April 2010 - 07:06 PM
Posted 28 April 2010 - 08:22 PM
Explore Scientific AR152, CF127 APO, 102mm APO & 80mm APO
Meade DS2130AT - Grab 'n Go
Celestron C8, Meade SN6
Starlight Xpress H-18, QHY10, Atik 460EX, 450C
Canon XSi &T2i & Orion Starshoot Imager V.2
Orion SSS III, DSI I and LPI Imagers
Posted 28 April 2010 - 10:00 PM
They screw onto the end of your eyepieces, then you must put your eyepieces in your scope and refocus.
I hope I'm understanding this correctly!
Posted 25 December 2010 - 07:31 AM
How do those specs determine how powerful of an eypeice will work in the scope?
I bought a Meade 5.5 Plossl 5 Element eyepeice and it does not work very well. I think it is
TOO powerful for my scope.
So, how does one determine how strong of an eyepeice I can upgrade to?
Posted 25 December 2010 - 10:39 AM
To get the mognification of a 2114, take the stated focal length of 1000mm and divide it by the focal length of the eyepiece.
For a telescope like a long tube reflector (f/8 or a focla length eight times its diameter) with a parabolic main mirror and a good secondary that is 20% the diameter of the main mirror or less, take the inches in diameter of the main mirror and multiply that by a constant to get the miximum power you can get out of it. At sea level, I have been told that constant is 40. At my house, with an elevation of about 650 feet, the number seems to be in the neighborhood of 50. I have been told that at the Okie-Tex Star Party, with very dark, still skies at 4200 feet elevation, some people have actually gotten 65 for a ratio.
For a long tube 114mm telescope (4.5 inch) about the highest power you can use under the best conditions is 225X. From that point, as the focal length goes down, so does the power limit. By the time you get to f/4, the practical limit for a very good scope is probably the 165X that I was getting.
Hope this helps,
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