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Celestron C8 vs Edge HD 8 for visual ?

John

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John

John

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As the title of the thread says really, what, if any, advantages does the Celestron Edge 8 have over a "conventional" Celestron C8 SCT when being used purely for visual astronomy ?

I've read the "blurb" but there is nothing like the word from actual users / owners ! :smiley:

Does the Edge system have any drawbacks in terms of cool down time or ease of  collimation ?

Thanks in advance :smiley:

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nightfisher

nightfisher

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I can only say this from having a quick read but it does sound like the edge is more for imaging and has extra glass built in, i would have to think that for visual a C925 might be a better choice

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ollypenrice

ollypenrice

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The Edge will not be terribly different in visual use, I don't think. I have had both original and flatfield Meades and not seen any great difference at the eyepiece. However, the resale value of the Edge will be, percentage-wise, far higher since you open up the market to imagers who are remarkably numerous in the community. If I were buying a new SCT I'd probably go for Edge/ACF for this reason, though I mostly buy on the used market.

Olly

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triton1

triton1

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I'll watch this thread because I was wondering the same thing having neuropathy in my legs standing at the ep can get quite sore and for two days afterwards painfull so methinks getting a scope with the ep at the other end so I can sit down would be beneficial so a 9.25 or 11 is what I was thinking about but when the word "edge" is in front if it the £££ seem to mount up.

ps visual only.

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alanjgreen

alanjgreen

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The edge version will cool down quicker as it has vents for cooling.

the edge version has mirror locks, useful for imaging with the larger c11 mirror. Just one more thing to fiddle with or ignore for visual.

the edge has built in reducer for imaging, not so useful for visual.

collimation is the same.

fastar is the same.

i decided that the same money spent on a larger c11 standard was more worthwhile to me as a visual user than a c925 edge. Aperture wins every time and does make a difference to the visual observer!

Or you could go the same size and use the saving for a nice dual speed micro focuser, now that would benefit a visual user! The price of the edge should mean you get a dual speed focuser. The c11 really needs dual speed, my c8 was fine without one.

Alan

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Chris

Chris

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Hi John, I've owned both and the Edge variant was the clear winner for visual compared to the Standard C8 XLT without a flattener. The stars can get blobby pretty quickly of axis with the standard C8, whereas, not only are the stars sharper on axis with the Edge, they remain so right up close to the edge. 

I've since used a Meade USA 8" SCT with a o.63 RF, and that came fairly close to the Edge, but the corrector isn't in the optimal place stuck on the back of the OTA. The optimal place is inside the scope and this is what the edge does, it places a corrector at the optimal point in the light path.

Google Celestron White Paper for spot diagrams of the standard C8, the Meade ACF, and the Edge HD, and the Edge comes out on top....I'd love another at some point.

The C9.25 also gets good reviews as the jewel in the crown before the Edge turned up, I'd like to try one of those one day.

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Stargazer McCabe

Stargazer McCabe

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5 minutes ago, alanjgreen said:

the edge has built in reducer for imaging, not so useful for visual.

Not so. The EdgeHD has a dedicated reducer that can be bought separately. It isn't "built in". Furthermore, I have actually found it useful for visual on many occasions. The reduction in focal length and associated alterations can yield benefits on certain nights and certain targets too. 

@John Through lurking and reading a handful of threads I'd draw the conclusion that your a man with a discerning eye. You appreciate the differences in eyepieces that some others wouldn't. You've auditioned Ethos, Myriads, top flight Pentax and Vixens and are one of the few who can identify their unique characteristics. 

I therefore would venture that to such an eye, the differences at the outer edge of the field of view between a standard C8 and an 8" EdgeHD would be marked to you...

And, dare I say it, there would be no point utilising such fine Oculars as you possess in a C8. Crisp to the edge eyepieces would show those small but significant imperfections in the C8 I'd venture. 

Best

Ed

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jetstream

jetstream

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41 minutes ago, Lockie said:

Google Celestron White Paper for spot diagrams of the standard C8, the Meade ACF, and the Edge HD, and the Edge comes out on top....I'd love another at some point.

Thanks for mentioning this, I just printed it.

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johninderby

johninderby

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8" Edge OTAs seem to go for about £900.00 or so. There's one for sale local to me but I'd have to sell something else to pay for it. :icon_biggrin:

Spent enough on hobbies lately anyway. Buying an Armortek Tank kit has kind of blown the hobby budget for a while. :sad2: A TEC140 would have been cheaper. 

            John 

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Chris

Chris

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Here's the white paper:

http://www.celestron.com/media/1360271/edgehd_whitepaper_final.pdf

Page 5 for the spot diagrams, they look about right from my experience with them.

I must say though, if you don't need the native focal length, adding a 0.63 reducer to a standard SCT does very much improve star shapes, just not quite as much as the Edge HD as said.

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John

John

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Just as well that I've not had a couple of glasses of wine tonight - my "trigger" finger on the "buy" button might have got itchy :rolleyes2:

Thanks for all the info folks. Lots to think about.

I seem to have a gap in my scope fleet between the 12" dob and the 5.1" triplet frac you see ...... want something reasonably compact / portable that rides on the Skytee II and HEQ5 well.

 

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si@nite

si@nite

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Not sure I buy into the fact that an Edge sct is any better optically than a standard xlt after reading comparisons on CN, granted the mirror lock is a plus, & for dso work, the field correction also useful end off! For planetary imaging or visual it will bring nothing to the game in my IMO, the corrector in the baffle tube can also be a problem when cooling too! Certainly not worth the price differential!

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