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I'm interested in purchasing a new telescope and have narrowed it down to the NexStar 6 SE vs. the Orion XT8.

I'd like to be able to get into astrophotography and read that having the Go-To (auto-tracking) is a must -- this would eliminate the Orion XT8. I really like the large(r) aperture of the XT8, but having the Go-To seems nice.

Is the image quality sharper on one or the other?

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With the site scope as it is, this belongs on Photography, but it's too old to migrate. –  David Z Dec 28 '12 at 22:43
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closed as off topic by David Z Dec 28 '12 at 22:42

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2 Answers

If you really want to do astrophoto, then you must use a driven mount, period. Goto is fine, but it's not a requirement, all you need is a tracking mount (a mount that spins around one axis, doing 360 deg in 24 hours, and spins steadily, that's all) - this is something many beginners are confused about.

Many people will tell you to not start with AP directly, but instead spend some time doing visual observations and kind of "get your bearings", so to speak. You don't need a scope to take awesome photos, all you need is a camera and a tracking mount, which you could even build yourself out of plywood and scrap components:

http://www.garyseronik.com/?q=node/52

That's because the critical requirements are a dark sky and, of course, the tracking mount. The light gathering ability of a larger aperture is secondary in importance, at least in the beginning.

The little NexStar is actually pretty "meh" for AP. You could get the dobson instead, spend some time learning the sky, and experiment with AP using a camera and a simple mount. You could even use the dob to take photos of bright objects such as the Moon or some large planets. Once you get all that stuff down pat, you'll make a much better choice of AP equipment.

Real AP gear is expensive and finicky - GEM mounts, Ritchey-Chretien scopes, apo refractors, etc.

The 6 SE is not much more than a toy, for AP. The XT8, on the other hand, is a decent visual scope. In their respective fields, they are not equivalent.

Finally, real AP is not entirely about the gear; a lot of it is about the knowledge that operates it.

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What are your thoughts about the Celestron C6-SGT telescope for AP? I've got a Nikon D3100 with the included 18-55 f/3.5-3.6 lens. I read that you can take decent photos if you get an f/6.3 Focal Reducer with that setup. I'd love to own a Dob, but like the portability of the SCTs. –  Trent Scott Sep 22 '11 at 8:24
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up vote 4 down vote accepted

Neither of these telescopes is really suitable for astrophotography. The XT8 has no tracking at all. The 6SE has tracking, but it is basically an altazimuth mount, so that the field of view rotates as it tracks, limiting you to very short exposures. Also, its drives use a spur gear system, which has a lot of backlash, making it really poor at guiding. While people have managed to take photographs with it, it requires superhuman efforts.

Quite honestly, I usually recommend that beginners in astronomy avoid photography in their first couple of years. Most beginners are nearly overwhelmed by basic astronomy: learning to operate the telescope and find objects in the sky, that trying to take photographs is just too much. I'd recommend that you purchase either of these scopes (because they're both excellent) and put photography on the back burner. Once you know your way around the sky, you can buy a proper equatorial mount and remount either of these scopes for photography. The problem is not with the scopes themselves (which are both excellent) but with their mounts, which are simply not designed nor suited for photography. When you do come to try photography, you will find that the minimum equatorial mount alone costs considerably more than either one of these telescopes: you're looking at a minimum of $1000 for a very basic astrophotography-capable mount.

As to the scopes themselves, I own a 6SE myself, and also have an 8-inch Dobsonian. Both are very useful telescopes, and both will be excellent for visual observation. The XT8 will show you more because of its larger aperture: more detail and brighter images. The main advantage of the 6SE is its compact size and portability. It's optics are quite good, but cannot compare with the XT8. If GoTo appeals to you, the XT8 is now available in a GoTo version, the XT8g. There is also the intermediate IntelliScope XT8i, which is my personal favourite. Its computer guides you to any object in the sky, but it uses manual power rather than motors, so is very quiet and low on battery consumption.

I disagree with Florin Andrei that the 6SE is "not much more than a toy." I have been very pleased with mine: it is well made and has good optics in a very solid compact portable package.

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Great points! I heard the same thing in some astronomy forums that the SE fork mount just isn't accurate enough for long exposures. What do you think about the Celestron C6-SGT with the CG-5 GT EQ mount? –  Trent Scott Sep 22 '11 at 8:25
    
This would be a much better choice if you're serious about photography. –  Geoff Gaherty Oct 7 '11 at 13:08
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