Would this work on an SCT or no?

[Shano592]

I'm pretty sure I already know the answer (no), but I thought I would hang it out there to publicly mulled over.

I found this on eBay :

http://www.ebay.com.au/itm/GSO-2-0-5x-Focal-Reducer-for-Telescope-GSRD2?item=110973621939&cmd=ViewItem&_trksid=p5197.m7&_trkparms=algo%3DLVI%26itu%3DUCI%26 otn%3D4%26po%3DLVI%26ps%3D63%26clki d%3D4884870040972930229

From what I can tell, it is likely to suit a Newtonian style scope.

Anyone care to disagree? Anyone using one on a larger SCT with great success?

FWIW, the same seller has a x0.63 reducer for SCTs. The x0.5 just piques my interest a little more.

[chrisp9au]

Yes, it would work on an SCT, if it had a 2" visual back.
Turns an F10 scope into an F5.

I have an Antares f/6.3 on my C6, but it's just a 1.25" job.

Cheers :thumbsup:

Chris

[Merlin66]

Yes, is the answer...but....
These eyepiece reducers (the 2" and the matching 1.25") are designed to screw into the eyepiece filter threads (M48 for the 2" and the b#$%@ 1.25" filter size) IMHO I think the optical performance is way below the std telescope reducer/ correctors which are, to a degree, customised to the optics of the OTA ie refractors @f7, SCT's @f10 etc and require a specific distance from the reducer to the image plane....
These are a poor mans answer to the problem, but not a maiden's dream.

[Shano592]

Hmmm.

I know that F/3.3 is basically wasted money due to heavy vignetting, and my concern is that f/5 will be similar.

Apparently, f/6.3 is quite reasonable, even though there is still some vignetting, it can be somewhat mollified with the light box.

I guess this is my question. Has anyone had experience with this focal ratio on a 10" SCT, and what were the results like?

If someone has used this GSO 0.5x reducer on the same setup, then that would be even better. Fingers crossed.

[Tony_]

Hello Shane,

I have a GSO 1.25" 0.5x reducer that I got for my 9.25" SCT. I only used it once or twice visually, I haven't tried imaging with it. I didn't like it at all - it does reduce the image and increase the field of view, but the view was not very good - in fact I hated it. I also have a 0.63x Hirsch reducer (which looks like the celestron one) - I don't particularly like that either.
I have imaged with the 0.63x reducer but the vignetting is much more severe than without it and it introduces coma - and usually I have a flat field.
To me the 0.5x reducer was a waste of money - but others may disagree. I think it is better to get the eyepiece with the focal length and field of view that you want rather than getting a cheap reducer.

Regards,
Tony.

[Fox]

Shane, a long time ago I got the Meade f6.3 focal reducer for my 2080C f10 8 inch SCT. It was fun for a laugh but hardly high end. There was huge distortion across the field, especially the edges, it had this coma and 'fishbowl' effect going on if I recall properly. The one you are talking about will be in the same ballpark, I'm sure. Cheers, Fox

[BlackWidow]

Hi Shane. I would suggest a 6.3 focal reducer and fiel flatter like the Mead, Celestron or Hirsch. There is also an Anteres if that's how it is spelt. I use the Hirsch on my 10 LX200 with greed results. You nest put the reducer after the electric focuser or you will get vignetting. I place mine onto a barrel and slide into the back of the focuser like you would an eyepiece. I then attach my camera ( QHY8) after theat. I have used spacers after the focal reducer so my CCD IS 105mm back from the rear glass of the focal reducer. The spacing from the focal reducer is critical the the f: ratio. The more you increase the distance the lower th f: stop. However this will then cause vignetting. The ideal space is around 105 mm. Should be able to pick up a Hirsch for around $60 on E-bay and around $80 for the other brands. You may also be able to pick one up on this site. I have tried the Meade and the Hirsch and found them to perform the same, but have not tried the other brands.



Hope this helps

Mardy

[Poita]

Is this for your 10" ACF?
The optec Lepus .62 has been shown to work on that scope:
http://www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Number/5187849/Main/5183536

[blink138]

you deffo get what you pay for........ personally i would not entertain the idea after all decent optics and the correction thereof, cost money!
just an opinion
pat