62 replies to this topic

[JimOfOakCreek]

The Celestron Binoviewer is the lowest cost binoviewer I could find. I am considering buying one but I really don’t know what I am doing. I have two scopes, an 8” SCT and a 4” F7 APO.

 

What are your thoughts? Any advice would be greatly appreciated.

 

[vtornado]

Hi Jim,

 

I have the williams optics bino's  the SCT will be no problem, but my 80 f/7 refractor does not come to focus, unless I add a real 2x barlow.

The OCSs that came with it do not bring the focus in enough.    I've only had two viewing session with it, but for lunar I find the image more

engaging with the binos than with the same mag and single eye piece.

 

I purchased mine used from another member, as I was nervous about the purchase, like will I like bino viewing enough

to justify the purchase.

 

I am using a 2x gso barlow and 20mm celestron plossl's

 

https://www.cloudyni...william-optics/

 

VT.

Edited by vtornado, 07 January 2022 - 08:26 PM.

[jprideaux]

I have a similar experience with the WO BV as vtornado. I think the Celestron BV is probably similar to the WO BV. One “trick” I do with my WO BV to reach focus with my fast refractor is to screw the 1.6x Barlow not into the BV but in the telescope-side of my Orion 1.25" Deluxe 45-degree Correct-Image Prism Diagonal. I can reach focus when I do that but not if I use the 1.6x Barlow screwed into the BV nose-piece. I’m just using the 1.6 Barlow because that is what came with my WO BV. A higher magnification Barlow probably would have worked screwed inyo the BV.

[akdwivedi]

I have the Chinese made celestron oem from AliExpress. I believe it’s similar to construction and design as celestron with a 20mm clear aperture on telescope side. It works very well with my celestron c8 sct without any cos. 
 

I had a surprise when it also came into focus with my svbony 90mm f/5.5 achromat with cos - 1.8x, 3x though I prefer to use it with 2x Barlow. On the achromat I am using this with 20mm and 10mm UFF eyepieces. The views are fantastic with UFFs rendering a more darker and clearer image than the 20mm.

[junomike]

Good BV to try and see if BV'ing is for you.

[JimOfOakCreek]

Good BV to try and see if BV'ing is for you.

My thought exactly. I’ll give BVing a try with a small investment to see how I like it. 
 

Thanks everyone for your guidance. 

[Astroyesmer]

Since many users on this thread probably own this specific binoviewer, is there any kind soul around that would measure the nose piece thread and report?

 

The reson I ask is Celestron themselves couldn't give me a definitive answer since it depends on vatiable manufacturers parameters...

 

I am trying to find out if this BV will come more likely with a M28x075 or with an M26x0.76 thread... or whatever else!

 

Plan is to thread it directly to a prism with the right adapter in order to shorten the light path...

 

So please CN users reach out to your calipers

[eyespy]

Hi,

 

My 20+ year old Celestron binoviewer works perfectly and has a standard filter thread size on the nosepiece. I usually screw an OCA directly to it.  For more power, I unscrew a barlow lens from its tube and screw that directly to the binoviewer nosepiece instead of the OCA.

 

Doug.....

Edited by eyespy, 04 October 2022 - 03:55 PM.

[Astroyesmer]

I suppose you are referring to the Celestron/Baader BV?

The one I am wondering abput would be the current black one with orange logo, similar to the Orion or WO BVs
...

[eyespy]

It’s this one from 2002 and there is a button logo for Celestron on the hinge the same as the photograph in the first post. No reference to Baader though. Looking at the Celestron website, the latest binoviewer doesn’t look much different than my 20+ year old version. Even the dimples in the handgrips and the aluminium case are the same. The details indicate that it also comes with standard 1.25” eyepiece filter threads.

 

Doug.....

 

 

Attached Thumbnails

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Edited by eyespy, 05 October 2022 - 03:18 PM.

[Astroyesmer]

Thank you!

And I confirm: the Celestron Binoviewer comes with a M28.5x0.6 male thread on the NOSE PIECE.

Therefore a FEMALE M28.5x0.6 thread on the BV itself WITHOUT the nose piece.

This info comes directly from Celestron technical service.

In other words, for those interested, this means if you order the Baader T2 prism diagonal and the Celestron BV, you can connect those 2 with a T2 to M28.5 adapter to shorten the light path.

Edited by Astroyesmer, 05 October 2022 - 07:11 PM.

[eyespy]

Just an add on. The chrome nose piece on my c2002 binoviewer does not unscrew. It is permanently attached to the binoviewer. The ability to remove it must be a more recent upgrade.

 

Doug.....

[Eddgie]

The Celestron binoviewer is a good performer with the compromises that are present in most entry level BVs.

 

The first is that the aperture is limited, which does limit your true field potential vs more expensive BVs.

The second is something shared by almost all inexpensive binoviewers, which is that they use a brass compression ring for eyepiece retention. This design can cause issues with many eyepieces having safety undercuts, but it is typical of the price point.

 

They are good performers though, with little to differentiate them from other models in the market at this price point. 

 

As someone mentioned, converting to T2 is pretty easy but I would not recommend you do this until you have had a chance to try them.

Why would you want to covert?  Well, if you are only 20mm short of reaching focus with your refractor, a T2 connection with a T2 diagonal will likely allow you to reach focus with no Barlow.

 

For the SCT, every mm of light path you can save will reduce the focal length by a bit over 3mm.  That means that changing to a T2 setup with T2 diagonal will reduce your focal length by 100mm. Optimizing with a 15mm Baader SCT connector can save give you back another 50mm of focal length.  

[Astroyesmer]

I have a 4" achro refractor and a 10" inch dob. I ordered the full party: Celestron BV, baader Q X1.3 oca, Baader T2 prism, Ring adapter to link the BV directly to the prism, low profile Baader 2" adapter to link the prism dirrctly in the 2" focuser... Ideally I can use the BV without the OCA; otherwise it will be decent minimal magnification with the Q... 

 

Will report as soon as all the gear arrives...

[YeloSub]

I have an orion BV, which is probably the same as the celestron/omegon/WO.

I use it with plossls in my 80ED and larger dobs (with barlow/ocs)

I have never tried the better BVers out there, but I love mine. Especially on planets and Luna.

[Eddgie]

I have never tried the better BVers out there, but I love mine. Especially on planets and Luna.

Yes, even the entry level BVs offer fine views. Now the Maxbright IIs are in a class by themselves due to the excellent desgin with twist lock self centering diopters, beautifully ergonomic focusting, and decent prism size, but as far as what you can actually see, the entry level BVs show you pretty much everything you can see in the more expensive units.

[Astroyesmer]

So, here is the report: I installed a linear bearing dual speed focuser on the refractor. In the focuser sits a 35mm extension tube, and in this tube a 2 inch dielectric diagonal. I take both out for binoviewing.

 

Binoviewing is:

 

A T2 prism Baader diagonal, with a low profile baader 2 inch adapter: that way the prism sits directly into the focuser with only 1mm inbetween them.

 

On the other side of the prism I put a ring adapter (T2 to M28.5). That way I can screw the binoviewer directly onnthe prism, without the nose piece. In between the binoviewer and the prism is only 1mm as well.

 

I can now use the 4" refractor with the binoviewer WITHOUT any barlow or OCA. I didn't expect this and was real happy when I realised I do not need the X1.3 nose bit of the Baader Q barlow I ordered for it... I tried my pair of 5mm and my pair of 25mm eyepieces and could focus with no issue. I also tried (with one eye only in the BV) my other eyepieces to check if all can focuse: they do! 32mm and 40mm plossl, Zoom, etc: all can focus. 

 

Now in the 10" dobsonian is another story. The Binoviewer (directly in the focuser with 1mm gap) can not focus without a barlow. Which means the high power eyepieces are a no go. With the X1.3 barlow in front of the BV though I can reach focus with my 25mm eyepieces, but it equals a barlow X3, so about 8mm, which is 150x magnification: I hope I will find a way to lower that number... but for the solar system it is acceptable.

 

The real issue now: locking the eyepieces in the BV with the compression ring does push the eyepieces slightly sideways, producing a double image. Impossible to enjoy, but loosening them fixes the problem. Not a satisfying solution though, so I came with one. And a really simple and effective one: electrician tape. Just a couple of loops around the recessed part of the cylinder, precisely applied and cut, and the eyepieces now sit inside the BV airtight and straight. A light turn on the compression ring and they are now secured and no more double image: time to enjoy! 1 night out, on the patio, only a couple hours, and only with the Moon and Jupiter. Reason was I was really trying the BV for the first time at night AND I was trying the 10" dob for the first time as well!

 

The refractor:

 

Impressive! With the BV, I could see the great red spot on Jupiter for the first time... Her 4 moons were never so big, and the planet itself of course also! I did not get the impression of less light, and I would say the impression of size increase of the views were about 3X. The moon was hidden by trees and the dob was cooling down: so I stayed with Jupiter for almost an hour, trying filters and barlows. One conclusion: I think I will never observe Jupiter in my refractor without both eyes!

 

The Dob:

 

Cooldown over, time to collimate. Took me a good 15minutes with the collimation cap. Once done I collimated my GSO laser, rechecked the dob collimation with the cap, and again with the laser. All good. The mirror temperature was perfect, time to observe!

 

Jupiter was gone behind trees, but the moon was now right over my yard. Too bright to observe anything else, so I put the BV into place, and BOOM! WOW... The Moon in a BV in a 10" dob is GIGANTIC! At 150X I could not fit her all in the lenses but talk about hovering over! So much definition in the craters! And the scale! I think this was the most incredible thing I've seen in a telescope so far... I simply cannot wait to use the BV in the dob for other objects now... And hopefully with less magnification although I have no idea how to achieve that...

 

So there it is: the Celestron BV reaching focus in a 4" achro with no OCA, keeping the eyepieces focal lenght, and incredible scale in a 10" reflector...

 

Let me know what you think or ask me anything about the accessories. And if you can help me reach focus in the Dob (1200x254mm) with less magnification I'll take it!

[jprideaux]

On the Dob with using the 1.3x Barlow which actually provides 3x (due to the long light-path after it), what is the position of your focuser when you reach focus? If it is nearly all the way out, then you might be able to find a more mild Barlow to reduce magnification a bit.

Another free thing to try (if focus most of the way out) is to try relocating your 1.3x Barlow to just before one of the eyepieces and st least see if you can reach focus with that one eye. If you can and if there are no other problems with the extra weight, then you could get a second 1.3x Barlow. A lot of ifs….

Another thing technically possible with the Dob is to move your primary mirror up enough to be able to reach focus with the binoviewer.

[Astroyesmer]

Not sure about the focuser position but I coumdn't find a milder barlow than 1.3 so far. About the barlow straight in the eyepiece I actually tried and it didn't work...

Since I am not ready or willing to touch the mirror I am still stuck at high mag for now...

[Astroyesmer]

I did reach out to Harry Siebert and I think I will get one of those OCAs. He proposed a X1.25 nose piece: not the X1 I hoped for but it is not too bad.

 

To be fair he also proposed a X1 but it was almost 400$... Twice the price of the X1.25.... I think I will get the X1.25.

Edited by Astroyesmer, 13 October 2022 - 09:58 AM.

[vtornado]

Not sure about the focuser position but I coumdn't find a milder barlow than 1.3 so far. About the barlow straight in the eyepiece I actually tried and it didn't work...

Since I am not ready or willing to touch the mirror I am still stuck at high mag for now...

If you are only a few mm out of focus in the Dob you can push the mirror all the way

forward with the collimation bolts, then walk the necessary amount backward to re collimate.

 

If you need more than a few millimeters this won't work.

 

Is it possible to get a thinner 2 to 1.25 inch adapter?

https://www.highpoin...2dba57410bc5ac6

[Astroyesmer]

Unfortunately it is not just a few mm... the mirror doesn't have enough way up for focus.

I actually already have the lowest possible 2" to 1.25" adapter from Baader:

https://www.firstlig...steeltrack.html

...(which allows me to use the BV without any barlow in the refractor) but it is not enough for the dob.

I already ordered the OCA from Siebert Optics, tbe X1.25 mag is fine since the BV wouldn't frame huge targets in the F/4.7 dob anyway; I can BV M42 or M45 or so in the refractor, and smaller objects with the dob.

[AngeloM]

So if the Celestron cost $279.95 I should assume the $187.00 Astromania Stereo Bino Viewer on Amazon.com is garbage?

[kroum]

Unfortunately it is not just a few mm... the mirror doesn't have enough way up for focus.

I actually already have the lowest possible 2" to 1.25" adapter from Baader:

https://www.firstlig...steeltrack.html

...(which allows me to use the BV without any barlow in the refractor) but it is not enough for the dob.

I already ordered the OCA from Siebert Optics, tbe X1.25 mag is fine since the BV wouldn't frame huge targets in the F/4.7 dob anyway; I can BV M42 or M45 or so in the refractor, and smaller objects with the dob.

Not cheap, but you can get a low-profile focuser.  Orion makes one with a variable drawtube so you can still focus on cyclops mode if you extend it, but it buys you a few cm of back focus if you retract it all the way.

 

There is also a 1.6x optical path corrector from Omegon that works with these binoviewers that screws into the 1.25” tube and provides a true 1.6x, so if your 1.3x Barlow actually does more than 3x, this could be useful to get you some more back focus.

 

Omegon Path Corrector for 1.25'', 1.6X bino-viewers https://a.co/d/91pE7NI

[kroum]

So if the Celestron cost $279.95 I should assume the $187.00 Astromania Stereo Bino Viewer on Amazon.com is garbage?

The internals of all of the lower tier prism binoviewers are the same.  They differ in the external plastic cladding, the eyepiece holders, and maybe the 1.25” barrel/threads.

 

Optically, they should perform identically.