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Getting ready to buy the 8" NexStar SCT and want to determine the best accessories.

2007-08-21 13:29:51 · 4 answers · asked by Anonymous in Science & Mathematics Astronomy & Space

4 answers

Yahoo Answers is a terrible place to ask serious technical questions like this, because very few people here know anything about telescopes. You'll do much better on one of the Yahoo Groups devoted to telescopes, such as:
http://tech.groups.yahoo.com/group/telescopes/
http://tech.groups.yahoo.com/group/nexstar/
http://tech.groups.yahoo.com/group/sct-user/

The 8SE comes with a so--so 1.25" diagonal, so a 2" diagonal is always going to be an extra. Be aware that, because of the diameter of the baffle tube in the 8", you may still get some vignetting with 2" eyepieces. Another alternative is to use a focal reducer/corrector which converts the focal ratio to f/6.3 and enables wider fields with 1.25" eyepieces...this is the route I've taken with my 6SE.

2007-08-21 13:58:12 · answer #1 · answered by GeoffG 7 · 0 0

The main advantage of the 2" diagonal is the ability to use 2" eyepieces to get a wider field of view. The larger eyepieces can give you up to about a 1.37° true field of view in an 8" f/10 SCT, while 1.25" eyepieces are limited to about 0.8°. There is no *light gathering* advantage to the 2" diagonal; that is fixed by the main mirror size.

The quality of the diagonal also matters, in terms of the clarity and sharpness of the view. An astronomical forum such as the Yahoo! telescopes group - http://tech.groups.yahoo.com/group/telescopes/ - is a better place than here to ask equipment questions.

2007-08-21 14:02:00 · answer #2 · answered by injanier 7 · 1 0

If you want to use very wide angle, low power eyepieces that only come in 2" versions, then you'll need a 2" diagonal. Otherwise, the 1.25" is fine. I have a 12" Meade LX-200, and I've only used the 2" diagonal once. That was while borrowing a friends Nagler wide angle eyepiece.

2007-08-21 14:06:08 · answer #3 · answered by I don't think so 5 · 0 0

As long as the QUALITY of the 2" is a better quality of optics and not just a cheap version then Yes, it is a much better option.

Golden rule: apeture, apeture, apeture.

The better the light gathering the better the seeing.

2007-08-21 13:42:37 · answer #4 · answered by B. 7 · 0 1

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