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Celestron Edge HD 11" v Orion Optics AG8"


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I know I'm getting ahead of myself, still in the planning stage of my observatory, but there's no harm in planning ahead....

To make the most of the new scope home I am looking to upgrade. I currently have one of the first 10" LX-200, now called a Classic, purchased from the old Farringdon shop of BC&F back in 1991...I think (it was a long time ago anyway). Still working I might add.

Given the confines of a dome (it's looking like being a dome at the moment) I'm looking at the Celestron Edge HD 11" (£2.5k) or an Orion Optics AG8 8" (£3.4k).

Taking into account that the AG8 is faster than the Celestron F3.8 v F10 but smaller aperture which one would you prefer for DSO's? Ultimately the endgame is to use it remotely for Deep Sky imaging ..... in the warmth of the house, not for me of course but for my wife (she has MS) and I'm sticking by that story :). I'm not ontop of Mauna Kea but 8 miles north of Brighton and even though the village has no street lights the quality of the AG8 optics may not quite be shown in their best light.

So any views on the above or even other suggestions would be gratefully received.

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Just a quick question before getting into telescopes, what mount do you intend to use because the two in your signature appear to be a little on the lightweight side for such heavyweight scopes by the time you add an imaging train to them, from memory the AG8 also needs a counterweight added in order to balance it in DEC :)

HTH

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Just to make it more difficult. If you are after low f-ratio, you can take a C11 EdgeHD down to F2 with hyperstar lens, which gives you an 11" F2 (£3.5k) vs 8" f3.5 (£3.4k).

Edit: Just noticed Orion is now listing their prices without VAT. The AG8 cost over £4k

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Optically, I'm not sure those scopes are substantial ugprades to a 10" LX-200. You may prefer them, but in terms of imaging results I am sure you would do best to work on mount, drive, tracking, control, cameras, image processing etc. (you'll have to ask an imaging expert for more specifics since I know nothing on the subject). In that situation, unless you could trade or sell the LX-200, I would upgrade that part last, but do consider compatibility with what you have in mind.

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what mount do you intend to use because the two in your signature appear to be a little on the lightweight side for such heavyweight scopes by the time you add an imaging train to them, from memory the AG8 also needs a counterweight added in order to balance it in DEC :)
Thanks for the heads up. I'll do some more investigation there. I was thinking of using my NEQ6 Pro SynScan given that Orion Optics actually sell the AG8 packaged with either the smaller EQ5 or my mount (the EQ6). They also offer a package with the Losmandy G11 as well.
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Just to make it more difficult. If you are after low f-ratio, you can take a C11 EdgeHD down to F2 with hyperstar lens, which gives you an 11" F2 (£3.5k) vs 8" f3.5 (£3.4k).

Edit: Just noticed Orion is now listing their prices without VAT. The AG8 cost over £4k

Yes, forgot about the hyperstar option and thanks for pointing out the VAT:eek:

Given my scope is a 20 year old vintage I am expecting noticably better optics to the offerings today....suggestions are this may not be the case:icon_scratch:

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I can't comment on the modern quality control, but the EdgeHD is essentially a standard SCT with a built in corrector/flattener. If you use Hyperstar, the corrector in the EdgeHD is bypassed so optically it will be the same as a C11 SCT with hyperstar.

Some versions of Meade 10" SCT can be converted for use with hyperstar. It may worth a look whether yours is compatible.

HyperStar Imaging

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I can't comment on the modern quality control, but the EdgeHD is essentially a standard SCT with a built in corrector/flattener. If you use Hyperstar, the corrector in the EdgeHD is bypassed so optically it will be the same as a C11 SCT with hyperstar.

Some versions of Meade 10" SCT can be converted for use with hyperstar. It may worth a look whether yours is compatible.

HyperStar Imaging

interesting... I had no idea that was the case... I thought it was a new prime mirror... how disappointing.

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interesting... I had no idea that was the case... I thought it was a new prime mirror... how disappointing.

On the positive side, all the EdgeHD remained Hyperstar compatible, where as Meade ACF with a different corrector design are not. The EdgeHD essentially give you 3 instruments in one, a f10 scope for planets, a f6.3 scope and a f2 Schmidt camera for dso.

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Have you considered also the Meade ACF? Quite competitively priced (though you need to budget for a focuser too) and seems to perform very well. Also reportedly works quite well with the Meade x0.63 reducer if you already have one. I do think it's worth upgrading if you are DSO-imaging with a DSLR or modern larger format CCD. A well corrected flat field is very desirable for imaging extended objects and coma on the older LX200s (I have one too!) really limits the size of the usable field.

Adrian

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Have you considered also the Meade ACF? Quite competitively priced (though you need to budget for a focuser too) and seems to perform very well. Also reportedly works quite well with the Meade x0.63 reducer if you already have one. I do think it's worth upgrading if you are DSO-imaging with a DSLR or modern larger format CCD. A well corrected flat field is very desirable for imaging extended objects and coma on the older LX200s (I have one too!) really limits the size of the usable field.

Adrian

Was concerned regarding reports of the electronics in the newer Meade scopes but given I'm likely to go for an OTA this would not be an issue (not thinking of an RCX). Also may have an remote focused lying around somewhere that might still be compatible...so the ACF is an option just not so flexible as the EdgeHD.

Good to hear you say that 20 years of manufacturing improvements would make a noticeable improvements and yes I would like to take wide field images of DSO's. Some of the photos on this site, such as Peter Shah's Orion Nebula, are truly enspiring.....unlike my first efforts on BW film in 1985 with the University of York's Astronomy Society's 8" SCT Celestron :)

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Orion really have AG8s paired with EQ6s? Don't get me wrong, I love my EQ6 (albeit my first fancy mount and with no frame of reference to others), and I've read about them just about coping with C11s, but an AG8 surely needs to go on something meatier.

I know when I bought my MN190 (modest in comparison to an AG8), my research had suggested that the EQ6 was good on scopes up to about 1000mm (a bit of a meaningless number, I know), and the FLO gents confirmed that the pairing was a good one, but that it was "maxing-out" the capabilities of the EQ6.

Someone considering a scope of that value and capability should doubtless be budgeting similarly considerable amounts on a support system for it.

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...The EdgeHD essentially give you 3 instruments in one, a f10 scope for planets, a f6.3 scope and a f2 Schmidt camera for dso.

Pardon my ignorance, Keith, but what's the middle configuration in those three? Is that with a focal reducer or something?

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Celestron is ('still') developing a reducer for the HD, and another US company, Optec, is making a reducer without flattener for the HD and ACF.

Optec Lepus Reducer Standard - OPT Telescopes

and the cloudynight thread where I learned about it.

Telescope Reviews: Edge HD Focal Reducer

btw, there is a AG8 on sale in the for sale section for £2800. I know RobB can't see it at the moment, but it's worth giving Peter Shah a pm.

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btw, there is a AG8 on sale in the for sale section for £2800. I know RobB can't see it at the moment, but it's worth giving Peter Shah a pm.
Better start posting some more then to get me past 50 :(. Given that it was Peter's images that drew me to the AG8....I wonder why he's selling it (if it is him of course) :)
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The AG8 and Edge 11 (or LX200 10 inch) are completely different beasts, and trying to compare them doesn't make much sense.

The AG8 is a super fast widefield scope, great for big targets but no good for most galaxies etc.

The Edge etc are better for smaller targets, but because of the long FL, are a lot more unforgiving of any mount issues.

The Edge is a long focal length improved SCT design. The improvements are mainly mechanical, but there's also a field flattener built in.

As said, the Edge scopes, Celestron C-series, LX200 classics and LX200 GPS scopes can be used with Hyperstar (I don't think the 12 inch LX scopes can though). The Meade RCX/ACF scopes aren't hyperstar compatible.

Currently, there are no available focal reducers specifically designed for the Edge or ACF series....both celestron and optec are going to produce them, but you can only pre-order the optecs at the moment, with no set date for availability.

This has put me off buying an Edge scope as I want to run it at around F6/7 most of the time.

I know that people have had good results using astropyhsics reducers with ACF scopes, but it depends on the size of the chip, and with large chips there is field distortion at the edges.

You really need to decide on what you want to image as both scopes are very different and will not cover the same targets.

Peter Shah's AG8, at £2800, would be a fantastic scope, and a lot less demanding on the tracking ability of the mount.

Cheers

Rob

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