Celestron Nexstar 8SE for astrophotography?

[roarke80]

Hi guys,

I'm a complete beginner and looking for a scope that will allow me to get into DSO photography.

I went down to widescreen center at Baker Street (wonderful people and great advice) and have narrowed it down to a few options. However since I live in a tiny flat in London, portability is a major concern for me. I'm also looking for a scope that is good for visual as well.

Basically I'm trying to decide between the Skywatcher 200P (or 150P), Evostar 80ED, and Celestron Nexstar 8SE.

The size of the Nexstar 8SE is really ideal, although it's quite pricey, but was wondering if you guys had any thoughts on how well it would perform for DSO photography? I understand it needs to be adapted for a shorter focal length, and also it comes with an altazimuth mount, is it possible to adapt it to an equatorial mount?

Otherwise I know the Evostar 80ED is excellent and portable, though expensive but I feel perhaps it's not as good for visual.

I feel like performance wise and value wise the 200P would be the best choice, and affordable as well, but it's really too massive for my flat.

I have pretty much decided to go with the EQ5 mount. I know it's not the best option for photography but it's kind of the furthest I can stretch spacewise, so it's just a question of deciding on the scope.

Sorry for being a complete newbie, but would really appreciate any thoughts on this and any other scopes that you would recommend?

Thanks!

Jess

[rowan46]

First Light Optics - Celestron C8-SGT XLT GOTO

This is the same scope as the nexstar on an eq mount it's about the same price. you are right it is not as good as the evostar for imaging but is better visually, the mount is a little better than the eq5 but noisier and to image you will as you say need a focal reducer. I think you may get some photos with this but it will not be as good as an evostar guided.

[DOBBY]

For long-exposure DSO photgraphy you need an equatorial mount like the HEQ5 not an Alt/Az like the nextstar

[roarke80]

Thanks very much rowan46, the C8 SGT looks like a really good alternative for me! The only thing is it's twice as heavy as Nexstar but at least I think it's still quite portable. How does the mount compare to something like EQ3 or EQ5?

[ollypenrice]

You find very few people imaging with SCTs and there's a reason for that. It isn't impossible but it is much, much more difficult than with something like the ED80, or another small refractor.

The main problem is the focal length. It's long, even if you use a focal reducer/falttener, which you would really have to do anyway. Long focal lengths need very accurate autoguiding and unguided imaging is just not worth it other than with very short FLs. Everyone talks about mount payload but when you get to long FLs you need to talk also about mount accuracy and that's why people spend £5K to £10K (or even £20K) on mounts. The NEQ6 is not an inherently accurate mount, it can cope with a focally reduced 8 inch SCT but it would not be dead easy, especially for a beginner.

Next F ratio. F10 is no good at all for DS imaging, especially with a DSLR which is time-limited by thermal noise.

Then there's optical distortion at the edge of field, addressed by the Edge and ACF versions which are more expensive. You need the F6.3 focal reducer/flattener which helps, but does not cure, the standard models.

Finally the focusers are not great for imaging.

You can image with Newts and get good results but they are more challenging than refractors.

AP isn't easy with a refractor but it far easier than with anything else.

My solution? Small imaging refractor on HEQ5 for imaging and mid sized Dob for visual.

It wouldn't be much dearer, if dearer at all, than the phantom one-scope-for-all option.

Olly