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SCT Reducer on Refractor.

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18 replies to this topic

#1 Ho lee

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Posted 07 June 2014 - 01:46 AM

Hello,

anyone tried to use Meade SCT F/6.3 Reducer on SV102,SV110, SV80ED scopes to reduce the F ratio? how is the image Quality?

Thanks
Ho

#2 T1R2

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Posted 07 June 2014 - 02:28 AM

I tried my celestron f6.3 on my AR127 f6.5 scope, I was messing around and it was impossible to get focus, I don't know how they would do on a long F15 scope. I don't think it will work.

#3 genedalton

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Posted 07 June 2014 - 10:06 AM

I have used the both the Celestron and Meade 6.3's on my binoviewer convertible SV 80ED (able to shorten the OT over four inches in bv mode), it gives me lots of back focus for the focal reducer. To me results are especially good for 'live view'...faster optics and wider view when feeding an image to my laptop with my Meade cameras. Gene

#4 Starman1

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Posted 07 June 2014 - 12:24 PM

Hello,

anyone tried to use Meade SCT F/6.3 Reducer on SV102,SV110, SV80ED scopes to reduce the F ratio? how is the image Quality?

Thanks
Ho

Since it both reduces the focal ratio and flattens the field, it could have good results. I don't think you'll find many who have doe this, though.
How would you attach it? A 2" male adapter with a male SCT 2" thread on one end? OK, easy to find.
Then how would you attach the star diagonal? A 2" SCT visual back piece? Ok, that's easy to find.
Come to think of it, it could be easily attached. :grin:

But the results?
I think you might be a guinea pig, here. Let us know how it works out.
It might create a stampede of people getting it, since it is less costly than many focal reducers.

#5 Jon Isaacs

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Posted 07 June 2014 - 01:07 PM

Hello,

anyone tried to use Meade SCT F/6.3 Reducer on SV102,SV110, SV80ED scopes to reduce the F ratio? how is the image Quality?

Thanks
Ho


Are you interested in visual or imaging?

Jon

#6 areyoukiddingme

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Posted 07 June 2014 - 05:25 PM

Well . . . you inspired me to give it a try! I have the celestron .63 reducer.

I removed the nose piece from my diagonal, and screwed the reducer directly to the diagonal. Then I screwed an extension off my barlow into the reducer, then into my 80mm F6 Orion apo.

I'm bumping up to the scope without reaching focus. ES 9mm, doesn't work. ES 14mm. Doesn't work. ES 20mm. Doesn't work. ES 30mm. Doesn't work. . .

Oh, what they heck. 55mm TV plossl. Whoooooooaaaaaa!

The views through my F3.8 apo are interesting to say the least!

So let's see: http://telescope-sim...r/#.U5OQXPldWCk

I have a 9.1 degree FOV!!!!!!!!!

Hey, binocular enthusiasts, how'd you like them apples? :roflmao:

#7 Ho lee

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Posted 07 June 2014 - 05:34 PM

Thanks, I will be using for CCD imaging with filter wheel. It will require 36mm from filter wheel to ccd sensor.

#8 areyoukiddingme

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Posted 07 June 2014 - 05:39 PM

. . . and I neglected to mention the 5.498x magnification!

Hmm, experimenting with my c6 visual back I still can't reach focus with relatively low FL eyepieces. But, straight through I can get my ES24mm (1.25) to focus.. .

#9 areyoukiddingme

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Posted 07 June 2014 - 06:05 PM

. . . and I can get the 55mm plossl to reach focus in my Televue 101. A mere 8 degree FOV this time :-)

The view isn't so nice though. The inherently flat field of the Petzval is probably the issue. My 80mm apo has curvature and seems to pair more nicely with the reducer.

#10 freestar8n

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Posted 08 June 2014 - 02:44 AM

Since it both reduces the focal ratio and flattens the field, it could have good results.



I have the celestron f/6.3 reducer and I assume it is the same basic design with two double convex doublets. You can tell just by looking at it that it can't flatten the field - because the SCT Petzval curvature will only get worse when you add it to the system. It does work well with my c11 to "correct" the field - mainly by reducing coma.

I don't know how well matched it is to sct's, but I don't expect it to work well with other arbitrary OTA's - though it will definitely reduce the focal length.

I would try it at the designed 105mm back focal distance and see how well it works. If it is bad, try other distances to try to tune it into a better optimal location. The best reduction may be more or less than 0.63x, and with a refractor at 105mm backfocus distance, it will be a greater reduction than 0.63x.

For something like video work with a small sensor, the reduction may have a net benefit - but for wide field work I would be surprised if it provides a good field with something other than an sct.

It's meant to correct the field of an sct, and the two main problems in normal sct's are coma and field curvature. It can't correct the Petzval curvature without a large system of positive and negative lenses, but it can address the coma. If you then use it on a scope with different, or zero coma - it may make things worse.

Frank

#11 Panotaker

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Posted 08 June 2014 - 07:06 AM

I can't afford a big chip camera, so I use a small scope to take wide field shots with my small chip camera. I use a Meade 6.3 on my Tak FS-60C.
Posted Image

I took this image with that setup and an SXV-H9
Posted Image
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#12 areyoukiddingme

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Posted 08 June 2014 - 12:11 PM

I'd say that's pretty decent evidence that it works!

#13 jwaldo

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Posted 08 June 2014 - 04:58 PM

Interesting that it works. Might have to give it a shot for my Zenithstar, since the original reducer/flattener seems impossible to find anymore.

#14 Panotaker

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Posted 08 June 2014 - 08:02 PM

I also use the Meade 6.3 FR on my Astro-Physics AP130-f/6 too. Here is a shot of The Horsehead Nebula with it. Keep in mind that I have a small chip camera, so it works good with that. I don't know how good it works with a big chip camera.
Posted Image

#15 Ho lee

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Posted 09 June 2014 - 04:27 AM

nice images. how about the spacing from reducer to ccd?

#16 Panotaker

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Posted 10 June 2014 - 01:55 PM

I didn't use any math to figure out the spacing. I just screwed it on to the front of the filter wheel and it worked. Details can be found here: FS-60C 6.3 FR

#17 Geo.

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Posted 12 June 2014 - 06:53 PM

I have one of William's short tube ZS 80s that was intended for bino use. Without the bino I suspect the 2" extension tube needed to attain focus vignettes the image. Works fine with f/6.3.

#18 mattyfatz

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Posted 13 June 2014 - 12:45 PM

I'm going to give this a try in my f11

#19 Manners2020

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Posted 24 September 2018 - 01:12 PM

Hello, what kind of adaptor eoukd I need for this ? I've looked at a few things online but I cant be sure. Thanks.


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