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Focal Reducer for 8 & 9.25" EDGE HD scopes - WHEN?

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#1 Jan Owen

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Posted 09 November 2012 - 02:35 PM

I keep looking for word on when focal reducers will be available for the 8" & 9.25" EDGE HD scopes...

And there's never an answer that's in the least reassuring... Had there ever been anything like a positive answer, I'd have already bought one of these scopes...

It seems like a great fumble on Celestron's part, sort of like the lack of a 6" EDGE HD... Is there anyone awake at Celestron?

#2 tonyt

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Posted 09 November 2012 - 05:26 PM

Don't the AP reducers work well with Edge scopes? I've seen good results with the CCDT67


#3 Jan Owen

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Posted 09 November 2012 - 08:23 PM

Thanks!!! I was aware of this item, but where I made my mistake in my earlier post was in not specifying that my interest in the reducer is for visual use, to achieve a wider equally flat field, in conjunction with a star diagonal & eyepieces... And within that context, of course, comes the question about whether one can use a 2" star diagonal with the new Celestron reducer (or any other one, as well) without reducing the effective aperture of the scope. Sorry I left out some critical data there!!!

#4 tonyt

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Posted 09 November 2012 - 08:35 PM

I assumed you meant for imaging use Jan, but I have used the CCDT67 visually and it works well. There can be some vignetting if in front of the diagonal but it does give a very wide field. It would obviously work without vignetting attached to the eyepiece but at a lesser reduction factor.

#5 Jan Owen

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Posted 10 November 2012 - 10:37 PM

Thanks, Tony... I'm fully appreciative of your experiences... And what you've said makes me think there may indeed be alternatives I haven't considered in lieu or Celestron doing what they've promised...

I don't know what adapters will be necessary to adapt the A-P reducer to an 8" EDGE HD scope for visual use (but I see you have an 8" EDGE, and likely know the answer to my question from personal experience, and probably have already answered my question, directly, or indirectly)...

#6 tonyt

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Posted 10 November 2012 - 11:16 PM

I only recently purchased the 8" Edge Jan and haven't used it with the reducer, but the CCDT67 has 2" filter threads so it can screw onto an eyepiece barrel or onto the front of a diagonal (with some vignetting when in front of the diagonal).

I used it in front of the diagonal on a Meade 12" and got a 1.3 degree FOV, measured by fitting alpha and beta Muscae in the field of a ES30mm 82 degree eyepiece.

If I get a clear night I'll try the CCDT67 attached to the eyepiece with the 8"Edge and let you know how much extra field there is.

#7 tonyt

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Posted 11 November 2012 - 08:27 AM

Tried the reducer on the 8" Edge tonight - when attached to the eyepiece there is a modest increase in the FOV (10% or so) with stars still good across the field. You could increase that by adding a barrel extender between the eyepiece and reducer.
Putting the reducer in front of the diagonal gives a larger increase in FOV but stars become aberrated in the outer field.

Personally I don't see any advantage using a reducer on an 8" visually since a 35 Panoptic or 30mm UWA gives a low power ~1.2 degree FOV anyway.

#8 Jan Owen

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Posted 11 November 2012 - 04:46 PM

Thanks for the additional follow-up & data!

And you're right; my 35 mm Panoptic should deliver just about 1.2 degrees, and the 41 mm Pan will stretch that a little further, to almost 1.4 degrees. I'd been hoping to get into the range of 1.5 degrees, but 1.4 is probably *close enough*.

So I probably CAN live without a reducer, using a 41 mm Panoptic as the last step. And it's simpler to just keep on feeding it eyepieces, without having to add intermediate optics...

Thanks again!!!

#9 tonyt

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Posted 11 November 2012 - 07:24 PM

You're welcome Jan - it's fun mucking around with optics.

1.2 degrees is about the limit with the C8 since the 38mm clear aperture at the rear cell will noticeably vignette the 41mm Panoptic field stop of 46mm. The 35 Pan or 30mm UWA variants are the best low power eyepieces for the C8.

I tried another reducer combination today: the CCDT67 can be screwed directly to the body of a WO diagonal, replacing the nosepiece, but at the expense of almost 3/8" of aperture due to vignetting inside the OTA. I'll see how it looks at night when I get the chance - it should give a much wider FOV.

Some SCT's are better suited than others for use with a reducer and the 8" is one of the worst for vignetting.

#10 Jan Owen

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Posted 12 November 2012 - 10:26 AM

I had an idea that might be the case (same size rear port as earlier 8" SCTs), but hadn't seen a spec sheet on them, and some photos I've seen in ads left open the possibility in my mind that they might have enlarged the port when they went to the EDGE design... Ahhh, well...

Truth is, my 8" Newtonian, with superb Mike Spooner optics can do everything as well or better, other than the compactness of the SCT design, and I already have the Newtonian... Heheheh!!!

Thanks again!!!

#11 REC

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Posted 12 November 2012 - 11:26 AM

You might want to look at the ES34SWA as a price alternative of the 35mm Pan. It's heavy, but works well in my 8SCT.

Bob

#12 Joe Cipriano

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Posted 12 November 2012 - 04:37 PM

News on both reducers in this post.

#13 Joe Cipriano

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Posted 12 November 2012 - 04:44 PM

To address Jan's comment about the lack of a C6 Edge (which I'd love to own): Per Kopit, a Edge 6 would not be financially viable - the cost to produce a 6 would be very close to the production cost of the 8.

#14 Jan Owen

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Posted 12 November 2012 - 05:43 PM

I'd been having a conversation about this, and this coincides with other data I've had indirectly from Celestron, but was heresay... This is MUCH more direct, but, sadly, pretty much as expected... Too bad... I'd sure like to own one (6" EDGE)...

Thanks for prying out data on BOTH subjects (reducer & 6" EDGE - both are items I've given more than a small amount of thought to...)... It's greatly appreciated!!!






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