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#1 Rand Barthel

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Posted 22 April 2013 - 04:10 PM

I am resuming my teenage interest in astronomy after a decades-long career-and-kids interruption. My scope is a golden-oldie Criterion RV6 6" f/8 reflector. I love it, but I find my self lusting after more aperture, Go-To, and AP capability. My search for the ideal dream scope had led me to the C9.25 Edge on an AP-capable German equatorial mount. But then the folks on the Eyepieces forum confused me by pointing out the advantages of a bigger truss-tube Dob for visual observing. That of course would mean no AP beyond possible planet and moon snaps. I now face a bewildering array of choices:

Plan A: Go ahead with the 925 Edge, perhaps on a CGEM, Orion Atlas, or iOptron mount

Plan B: Bag time-exposure AP, and buy an Orion XX12g truss-tube go-to Dob for a good deal less money

Plan C: Approach this in phases. Get a CGEM or similar serious AP-capable mount, put the RV6 OTA on it initially which would be huge overkill, but eventually move up to an SCT and/or a 10" f/5 or so Newtonian and try my hand at AP with that.

Do people actually do AP with Newtonians? Most of the chatter seems to feature catadioptrics or refractors, but it seems that the main issues with Newts have to do with coma/field curvature and the mount required to hold a big tube steady enough.

Another question I have is the "Edge" question: EdgeHD optics come at a big cost premium, especially in the 9.25" and larger sizes. Is EdgeHD better than the field flattener/correctors I see people using with traditional SCTs?

So many questions, so much money riding on them...

#2 DaemonGPF

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Posted 22 April 2013 - 04:24 PM

You could always add a field derotator and/or a tracking base to one of those big behemoth truss-tube dobs and satisfy big aperture for visual while getting in to some AP.. It's been done.

Aperture isn't king when it comes to AP, not at our level anyway. Many fantastic, and even top-notch images come from the smallest of instruments, i.e. 80mm APOs or smaller in some cases. If you're looking for a jack-of-all-trades sort of rig, consider a compound setup. A nice sized SCT coupled with a small refractor. Then you have short and long focal lengths for AP, but decent aperture in the SCT for visual. Or, get whatever setup for AP, and slap a 10" dob on the mount for visual since on an EQ you're completely interchangeable. A CGEM or an Atlas would handle a 10" dob just fine for visual, and even some AP if you dialed it in right (just not optimal nor preferred due to size, lever arm, etc.). Be aware that you could be in for some, well, "interesting" viewing positions with a big dob on an EQ mount.. Been there, done that.

Edge HD scopes are great for visual, and great for AP as they have many enhancements over the prior gen SCTs, but, depending on what you do, those advantages could be negated or rendered pointless - i.e. if you add a Hyperstar to the setup.

Atlas or CGEM are both extremely capable mounts and you'll find many accomplished astrophotographers on both. Serious AP mounts? Sure. Top end AP mounts? Not even close (at least on cost). But in my humble opinion, they are a far cry from "entry/base" level in terms of performance.

#3 Ranger Tim

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Posted 22 April 2013 - 06:29 PM

I think your instincts are good. The C9.25 is an excellent scope for AP or Visual. Put it on a strong mount and you're in business. You may tire of the AP rabbit hole quickly (many often do) and you will still be left with a fine visual set-up. If the AP bug really bites hard, then you can increase the stable of scopes to include short and medium focal length, Hyperstar, larger and faster newts, etc. The night sky will be your oyster. BTW, I don't have an SCT but secretly wish I had a C9.25 Edge. SSSSHH! Here comes my wife...

#4 Momerath

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Posted 22 April 2013 - 06:58 PM

I am a big believer in getting what you want. If you want the C9.25 Edge, not only will you be getting a great scope but you will be happy you got what you wanted.

The views in mine are absolutly outstanding, and I am glad I got the one I did. Now I just need to get that 130 refractor

#5 Rand Barthel

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Posted 22 April 2013 - 11:23 PM

Looking further at this, I notice that the 8" Edge is $1000 less than the 9.25" Edge. At that rate I could buy the 8" Edge and a 10" f/5 or so Newt OTA and have money left over for a field flattener or some other AP accessories. Tempting.

#6 fishonkevin

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Posted 23 April 2013 - 10:00 AM

You haven't even mentioned camera yet.
AP = Accessories( Wallet )

#7 Ranger Tim

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Posted 23 April 2013 - 09:38 PM

Rand,

The 8 inch Edge is a great option too. Visually you may never be happy once you get spoiled by a large aperture dob, but they are a pain to transport and set up. I just don't see myself working that hard at home.

I think your last comment was also right on target. Good luck in your search.

#8 munchmeister

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Posted 24 April 2013 - 02:17 PM

Just another humble beginner here. One thing has not been mentioned is the post processing time and effort for AP. It is hugely time consuming to get the kind of "holy cow" images that you will see on CN. Not that you can't get a start, get some good starter images. But the post processing, like all of AP, is not for the faint of heart (or wallet).

I have wallowed around in all aspects of this. Started with a cheap refractor, then got a 6" Celestron SCT, then a solar PST scope, NexImage 5 video camera, iOptron SkyTracker.... etc. (see sig). All this flailing about has not made me a better astro photographer, hence my warning about the time and dedication needed to get anything even remotely qualified as an astro photograph (and I've been an avid amateur photog for 43 years).

I do agree with others that the Edge scopes are really, really good instruments. Put that on a decent mount and you could get a really good start. And if you mounted a small, wide field refractor on top (72-80mm aperture width), you would have a system that would last a long time and get you pretty deep into this for quite a while. Celestron's new AVX mount is relatively low priced (~$800) and is being pitched as the astro photographers entry mount of choice. iOptron has also introduced the iOptron ZEQ25 a "new innovation in mount design. The new iOptron “Z” design mount puts the weight of the payload at the center of gravity allowing for greater natural stability. Given its payload capacity, this means the “Z” designed mount is unusually light—a nice benefit when setting up at a remote site. Other features include an adjustable counterweight bar to prevent obstruction with the tripod. And polar aligning is quick and accessible all the time since the polar scope is not blocked by the declination shaft." Also around $800.

If I were starting again, that is where I would go. Get one of these mounts, add either an Edge 8" or just a 6" or 8" and worry less about coma or other distortions and just see if you can even GET an image, then start shooting subs and learn the whole stacking, stretching, post processing process.

Or, just get that big Dob and get some nice views on warm summer nights. Either way, you win. ;-)






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