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Celestron Edge 1100 HD cgem-dx vs. ES 127mm APO At

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#1 BenB85

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Posted 02 March 2013 - 05:24 AM

Hello all,

In your opinion what is the better setup for visual and astrophotography for a beginner scope that will last years:

Celestron Edge 1100 HD cgem-dx with hyper star
Or

Explore Scientific 127mm ED Apo on Atlas mount with televue .8 reducer?

Thanks!

#2 fmhill

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Posted 02 March 2013 - 08:45 AM

Interesting question and a good one... It so happens I have both those with the exception of the Atlas mount. I use a ES127 ED/APO on a CGEM DX mount for most of my imaging and also have a EdgeHD 11" on a Losmandy G11 mount which I use mostly for planetary viewing/imaging...

The answer to your question is for a first imaging setup, I would recommend the ES127 ED/APO and I prefer it on the CGEM DX mount due to the CGEM DX mount height, it is a tall mount.

The EdgeHD 11" SCT is not a OTA for the faint of heart, it is a bear to get to track well due to its long focal length and has too much apparent magnification even when used as a prime focal imaging setup. Using it with a hyperstar setup is a good solution to imaging with it but complicates the imaging process making the ES127 my first choice for imaging other than for using the EdgeHD 11" for very distant/small objects and planetary imaging...

To my way of thinking the EdgeHD is strictly an advanced level OTA, not a begginer's scope... If your interest in astroimaging is diverse, you will most6 likely end up with a EdgeHD as a second scope once you have gained experience.

In both cases, you will want to allow in your budget for a guiding system, a autoguiding package is critical for imaging with either of these choices...

#3 Eddgie

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Posted 02 March 2013 - 09:48 AM

My suggestion is to go to the Refractor Forum and look for the post where this guy bought a 6" APO and is now complaining.

The title of his Post is something like "6" APO is not good for wide field imaging."

Duh.

See, the requirements for imaging are very complex. You think you want to image, but the big question is "What do you want to image?"

The EdgeHD will be good for smaller objects where you want a bigger image scale (small nebula like the Ring Nebula and small clusters). It will also be excellent for planetary imaging even with inexpensive color web cams. At f/2 with Hyperstar, it can also do wide fields, but this adds a lot of cost because of the special camera, or you can get the focal reducer to go to f/6.3, but this is also expensive.

The smaller refractor will excel at very large targets like large diffuse nebula and large clusters, but you sacrifice image scale.

You should also look at your budget for cameras and things like focal reducers.

These are two very different scopes when it comes to imaging (for visual also, but that is another story).

Here is one suggestion I often give.

Right here on CN, there are forums for deep sky imaging and for planetary imaging.

Spend some time looking at pictures and ask yourself "Which of these look like the kind of imaging I want to do?

And when you have found them, look at the kind of scope that was used and you have your answer.

Otherwise, your answer will be

Oh, the EdgeHD 11 is better

or

The ES is better.

Both of these are excellent telescopes, and most people would say that you can't go wrong with either one.

But ask the guy with the 6" APO in the Refractor forum about that. My guess is that he will tell you that you can indeed go wrong.

Figure out what you want to image, and buy the best scope for that.

Or we may see a thread in the ______________________ forum that __________ scope isn't good for imaging __________.

And that would be sad.

#4 BenB85

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Posted 02 March 2013 - 11:17 AM

My suggestion is to go to the Refractor Forum and look for the post where this guy bought a 6" APO and is not complaining.

The title of his Post is something like "6" APO is not good for wide field imaging."

Duh.

See, the requirements for imaging are very complex. You think you want to image, but the big question is "What do you want to image?"

The EdgeHD will be good for smaller objects where you want a bigger image scale (small nebula like the Ring Nebula and small clusters). It will also be excellent for planetary imaging even with inexpensive color web cams. At f/2 with Hyperstar, it can also do wide fields, but this adds a lot of cost because of the special camera, or you can get the focal reducer to go to f/6.3, but this is also expensive.

The smaller refractor will excel at very large targets like large diffuse nebula and large clusters, but you sacrifice image scale.

You should also look at your budget for cameras and things like focal reducers.

These are two very different scopes when it comes to imaging (for visual also, but that is another story).

Here is one suggestion I often give.

Right here on CN, there are forums for deep sky imaging and for planetary imaging.

Spend some time looking at pictures and ask yourself "Which of these look like the kind of imaging I want to do?

And when you have found them, look at the kind of scope that was used and you have your answer.

Otherwise, your answer will be

Oh, the EdgeHD 11 is better

or

The ES is better.

Both of these are excellent telescopes, and most people would say that you can't go wrong with either one.

But ask the guy with the 6" APO in the Refractor forum about that. My guess is that he will tell you that you can indeed go wrong.

Figure out what you want to image, and buy the best scope for that.

Or we may see a thread in the ______________________ forum that __________ scope isn't good for imaging __________.

And that would be sad.


I did exactly that to the tune of 40-50 hours.

The ES 127 with televue .8x reducer gives a similar wide field image scale as the c1100hd @f/2 with hyper star. Both setups are roughly the same cost at around $5,000-$5,500.

So I thought the ES was the option to go with for sharpness and portability at the expense of imaging time required, compared with c1100@f2.

I was expecting brighter images with a 127apo. I've never looked through one before but from all I read I expected it to be superior to a cassegrain.

#5 Raginar

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Posted 02 March 2013 - 11:54 AM

Honestly, if you're investing in a nice setup, exposure time isn't an issue. Whether or not a CGEM DX can handle the moment arm on a long refractor with a camera, etc, attached is another story.

The other side of it is whether you want to deal with a hyperstar. You have to manage your cables to create pleasing diffraction spikes (and you have to want to have diffraction spikes).

I dunno what you mean by brighter images. I'm assuming you're relating their focal ratios and assuming one will give you a brighter image at a given exposure. You correct this by.. increasing your exposure with the refractor :). It's not that big of a deal unless you're compensating for 'other' issues such as poor polar alignment or mechanical quality.

For example, I have an 8" f/4 newt and a ED80 f/6.5. I can make the ED80 images 'as bright as' my newt pictures by increasing my exposure.

Finally, when I'm buying equipment I use astrobin. I search for the camera/scope/mount that I'm thinking about buying and go find images that were taken with it. When I see some good examples, I PM the guy and find out what his experience has been with his setup and what he would've done differently. Most people are completely honest about the amount of work involved in a setup and are more than happy to give their opinions on a set of gear!

My recommendation is to start small. Get a great mount (G11) and a nice widefield refractor (ED80) with a finder guider rig. Once you figure that out, you can get any scope you want and move on from there.

Good luck :D

#6 drwho

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Posted 02 March 2013 - 12:03 PM

While I'm not an imager, many in my club are. Almost to a person started with a small refractor either a 65 or 80mm. The images were fantastic and over the years have moved to larger refractors (primarily) and only a few to SCT hyperstar setups because of it's increased complexity.

Based on their experience, I'd say start small and simpler (refractor).

Best of Luck in your explorations!
JerryK

#7 George N

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Posted 02 March 2013 - 03:46 PM

I have a friend (visual only) who owns: the 127ED, both C-11 and C-14 tubes, and both a cgem-dx and cg-5 mount. I don’t know, but I usually see him using both the refractor and C-11 at star parties. They are very complementary scopes for visual observing.

I personally mostly observe with my 127ed and CG-5 mount, plus my Obsession 20 – set up side-by-side.

#8 EFT

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Posted 03 March 2013 - 12:28 PM

Very different scopes for generally different purposes. However, some amazing things can be done with the C11 and Hyperstar. Surprisingly, if I had to compare the two scopes mechanically, I would rate the EdgeHD better. The ES scopes are nice, but their focusers tend to be marginal, especially for AP. Slap a nice aftermarket focuser on the ES and you have something, but you spend another $600+ to do that.

My personal preference for the mount is the CGEM DX. However, the massive tripod is an issue.






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