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0.63 Reducer/Corrector for '77 C8? (visual only)

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#1 B 26354

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Posted 26 March 2020 - 12:39 PM

As I've explained in various other posts... I just began looking into astro-photography about four years ago... but I've been a dedicated DSO visual observer for almost sixty-six years.

 

I bought my C8 new in '77, and de-forked it about a year ago. It's now on an un-driven Orion SkyView Pro EQ mount, and I use it exclusively for visual... sometimes by itself, and almost always while I'm concurrently doing AP with one of my refractors on the iOptron CEM25P.

 

Over the years, I've often considered getting a Celestron 0.63 reducer/corrector, just to "brighten" the image in the eyepieces a bit... but I've always ended up deciding that it probably just won't realistically be worth it. Where I'm living now, however, my skies are clear and dry quite often, and are mag ~5.3 to my north, east, and south. So I'm currently getting lots of use out of the C8... and I once again find myself wondering about the real-world practicality of getting one.

 

Three things....

 

The Celestron reducer/corrector seems to generally get better reviews than its Meade counterpart. Is it?

 

Is there a specific "version" of these reducer/correctors that will actually fit onto my '77 C8 and accommodate its 1.25" visual back... or will I need to find adapters? If so... which adapters?

 

I'm aware that Starizona makes a four-element 0.63 SCT reducer/corrector, but it's quite a bit more expensive than I'd want to spend for this device's intended use, even though my C8's optics are excellent. Since I'd only be using a reducer/corrector for visual... is it likely that I'll be reasonably happy with the results (i.e., the overall "sharpness") that the much-less-expensive Celestron (or Meade) reducer/corrector would give me? And most importantly... will any of these reducer/correctors honestly give me a "noticeably" brighter image of things like the brighter galaxies and nebulae... or is their real benefit primarily photographic?

 

confused1.gif



#2 Magnus Ahrling

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Posted 26 March 2020 - 08:10 PM

I have an old (but good) `73 C8. I use a Celestron 0`63 focal reducer + a 1.25" Baader Clicklock visualback + 1.25" WO diagonal. (I have also used the standard vb but once using the clicklock vb I just can`t live without itwaytogo.gif)  For me it works fine for visual.  Images won`t be brighter but the field of of view will be wider as you turn the standard 2000mm focal length into 1280mm. I almost always use the focalreducer. In my opinion a "must" have accesory with an SCT.

I am a visual observer only!

 

 

Magnus


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#3 RalphMeisterTigerMan

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Posted 26 March 2020 - 08:41 PM

This was a big problem back in the mid-1980's. Some companies were actually advertising that an f/5 scope will give brighter images than an f/10. If the scope happens to be an 8" reflector, it will give you the brightness that an 8" can give, no matter the f/ ratio.

 

The benefits that an f/6.3 reducer corrector will give is a lower magnification and a "wider" field of view. For photography, it will lessen the time it takes to take a certain image. Imagers will be able to explain it better.

 

But, the f/6.3 will allow you lower magnifications and a wider field. Sorry, but no increase in brightness. And an f/3.3 is usable for photography only, will not work for visual.

 

Good luck and ckear skies!

RalphMeisterTigerMan


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#4 B 26354

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Posted 27 March 2020 - 12:07 AM

Big thanks to both of you.

 

I've been using SLR cameras for "terrestrial" photography since the mid-sixties, so I completely understand the effects that changing focal-ratio has on photographic exposure. I also understand that changing my C8's focal-ratio from f/10 to f/6.3 would give me decreased magnification and a wider field of view.

 

I knew these things back when the Celestron reducer/correctors were first introduced... but at the same time, I seriously questioned whether or not they would make any difference at all, visually, in terms of brightness. It didn't seem to me that they would... but I've never run across any comments on that aspect, one way or the other. Having both of you affirm that my suspicions were correct, is very gratifying... and truly helpful. I have no interest at all in using my C8 for AP... so you've enlightened my understanding... and you've also just saved me a needless expense.   waytogo.gif    grin.gif


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#5 munirocks

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Posted 27 March 2020 - 02:13 PM

I got a reducer a few months back and was amazed at the width of the view. For visual you use it to gain width - not brightness. The view is a whopping 60% wider and using it was the first time I got the entirety of M44 and M45 in the field of view (but not at the same time). The double cluster had room to flex it's beauty without feeling cramped. Everybody needs one. I now use it more than my powermates. If you have light pollution, though, the background sky will not be as dark.


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