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need BV reducer

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#1 gonzosc1

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Posted 26 November 2012 - 07:48 PM

got a use Orion BV but no reducer with it. what should I use??

#2 Bob S.

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Posted 26 November 2012 - 07:50 PM

Contact Harry Siebert and Siebert Optics. He will have one for you.

#3 gonzosc1

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Posted 26 November 2012 - 08:04 PM

Contact Harry Siebert and Siebert Optics. He will have one for you.


thank you sir.. :bow:

#4 avenger

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Posted 27 November 2012 - 07:35 AM

Yes, call Harry Siebert he makes all types of reducers and optical correctors for all binoviewers.

#5 gonzosc1

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Posted 27 November 2012 - 05:10 PM

thanks guys! another BV question here.
should I use the standard SCT screw on dia? or can I, or should I get a true 2" visual back for the ota. I know nothing about the celestrons. can a peterson eye opener be used on them like with the meade ota's?

#6 avenger

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Posted 27 November 2012 - 05:52 PM

You can use a Peterson visual back on a Celestron 11", 14". I do not know if the 8" can use one.
Yes, you can use a 2" screw on diagonal with the binoviewer with no problem at all.

#7 covey

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Posted 27 November 2012 - 06:01 PM

The Peterson is not compatible with the C8.
The standard visual back that came with the C8 works just fine. So does a 2 inch SCT screw on diagonal.

#8 gonzosc1

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Posted 27 November 2012 - 06:04 PM

You can use a Peterson visual back on a Celestron 11", 14". I do not know if the 8" can use one.
Yes, you can use a 2" screw on diagonal with the binoviewer with no problem at all.


I will have a C9.25. will using the eye opener improve contrast with the bigger app when using the BV? I remember using one on my meade 10" and the difference was slight but it was there.

#9 avenger

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Posted 27 November 2012 - 06:13 PM

I forgot about the C 9.25, that is a great scope. I would think just the advantage of being able to open the visual back on the C 9.25 up to 2" would be the way to go. More light throughput would not hurt at all.

#10 DaveJ

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Posted 27 November 2012 - 06:37 PM

I will have a C9.25. will using the eye opener improve contrast with the bigger app when using the BV? I remember using one on my meade 10" and the difference was slight but it was there.


I hate to burst your bubble, but the Celestron 9.25" doesn't have the 3.25" threaded back that the Peterson "Eye Opener" attaches to... you have to go to a C-11 for those 3.25" threads. Adding to the annoyances, the 3.25" back on the Celestrons that have them is not the same threads as the 3.25" back on the 10" and larger Meades. It's a laugh a minute, isn't it? :bawling:

#11 gonzosc1

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Posted 27 November 2012 - 07:01 PM

I will have a C9.25. will using the eye opener improve contrast with the bigger app when using the BV? I remember using one on my meade 10" and the difference was slight but it was there.



I hate to burst your bubble, but the Celestron 9.25" doesn't have the 3.25" threaded back that the Peterson "Eye Opener" attaches to... you have to go to a C-11 for those 3.25" threads. Adding to the annoyances, the 3.25" back on the Celestrons that have them is not the same threads as the 3.25" back on the 10" and larger Meades. It's a laugh a minute, isn't it? :bawling:


LOL that figures :foreheadslap:
well it was a good idea while it lasted!!

#12 Starman81

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Posted 26 December 2012 - 07:09 PM

After some indoor testing, focusing on objects about 25 feet away, I am happy to report that my f/6.3 focal reducer works on my 8SE. This is with my WO screw-on diagonal and Denk II's using TV Plossl 32's and Vixen LVW 22's. Have others had similar experience? Can I expect it to work without issues during night time observing?

#13 Eddgie

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Posted 27 December 2012 - 11:04 AM

It is probably reducing the aperture to something like 6", but if you can see stars, I guess it works.

Again, you are likley using a 6" or 6.5% scope with a 42% obstruction, but hey, that only matters if it matters to you.

#14 faackanders2

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Posted 27 December 2012 - 05:41 PM

It is probably reducing the aperture to something like 6", but if you can see stars, I guess it works.

Again, you are likley using a 6" or 6.5% scope with a 42% obstruction, but hey, that only matters if it matters to you.


Sometimes all you want is a wider view to get multiple objects, large objects, comets, milkyway, etc.

#15 Starman81

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Posted 29 December 2012 - 05:09 PM

It is probably reducing the aperture to something like 6", but if you can see stars, I guess it works.

Again, you are likley using a 6" or 6.5% scope with a 42% obstruction, but hey, that only matters if it matters to you.


I have not 'seen the stars' yet using this setup with all the clouds and snowfall we've had recently. I find thath BV'ing takes A LOT of experimenting and patience and then sometimes you don't even know what magnification/FOV of view you are getting... It is starting to frustrate me a little! :bangbangbang:

#16 faackanders2

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Posted 01 January 2013 - 02:49 PM

After some indoor testing, focusing on objects about 25 feet away, I am happy to report that my f/6.3 focal reducer works on my 8SE. This is with my WO screw-on diagonal and Denk II's using TV Plossl 32's and Vixen LVW 22's. Have others had similar experience? Can I expect it to work without issues during night time observing?


Focusing binoviewers inside requires alot of outfocus. Looking at objects at infinity will require infocus. When I first got my binoviewers, I made the mistake at trying to focus at XMAS lights (due to cloudy skies) and required a 2" extension (outfocus) to focus. Practice on something much farther away (if the skies are not clear).

#17 Eddgie

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Posted 01 January 2013 - 05:09 PM

Binoviewing is one of the most complex equipment requirements in amateur astronomy.

And it gets worse with SCTs because everything chages every time you move the focuser knob. The focal length, the magnification, and even the aperture.

And don't let me discourage you. You're right in that if the only thing you want to do is get a wider field of view and don't mind the aperture loss, then by all means, do it.

But rememeber to to take off the focal reducer when you don't need the widest field possible, because it has a very serious effect on the apeture and contrast performance of the telescope.

That is my main concern for you. To me, the effects of aperture reduction are profound, and I just can't bear to loose aperture even to get a wider field of view. But that is me. If I can't look at it at full aperture, then I would rather turn my scope to something that will fit in the field of view (and there are thousands of targets that easily fit into a 165x binoviewed feild fo the C14).

But that again is me. I am one anal puppy when it comes to things like this and I know it.

I find that many people though are thrilled with this kind of compromise (loose a lot of aperture to get some true field increase).

And that is why I say that if it works for you, it works for you. But I wanted to make you aware that this configuration has a serious consequence, and knowing that, you may want to resort to it only when you need the extra true field.

#18 Starman81

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Posted 05 January 2013 - 01:42 AM

Ed and Ken, thanks for the advice. I really don't need more aperture loss, so I am going to plan on BV'ing without the focal reducer as the typical setup and only use the FR when specifically trying to frame certain objects or view the moon and planets.






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