Binoviewer Help

[Kronos831]

Hello guys! Its  me kronos, and i have been wondering about getting a binoviewer sometime in the near future!

I do have some questions tho, (Binoviewer Budget Up to 200Euros *shipping and vat included)

 

1)Which One??( Please recommend sites from the EU only,Brexit is happening in a few days and i live in the EU so rip FLO for me)

2)Can i use my barlow lens on it(the lens part) i have a BST Barlow Or do i need to buy another one

3)Can i use 1.25" filters ? and if so, can i stack them with the barlow lens?

[Ricochet]

1. TS Binoviewer Lots of the cheaper binoviewers are very similar internally but this one is supposed to have the best eyepiece clamps. If you buy a different one make sure you go for one with a self centring twist lock clamp not one with three grub screws which can push the eyepieces out of collimation.
    
2. So long as the binoviewer has a standard filter thread on the nosepiece and a barlow cell has the same thread then yes. This is the normal arrangement on most binoviewers and barlows. You may find that your particular barlow does not allow the binoviewer to reach focus in which case you will have to buy and try another barlow. I bought one that looks like the FLO Astro Essentials barlow on eBay direct from China very cheaply and it gives about 3x magnification in my BV with a touch of outfocus needed.
    
3. If the barlow lens you are using has a filter thread on the bottom then yes you can use filters. I wouldn't be messing around with trying to fit a filter between the binoviewer and the barlow. With my BV barlows one has a filter thread and one doesn't (the cheap one from China), but I have a 2"-1.25" adaptor that is threaded for 2" filters so I just use 2" filters. I only use binoviewers on solar system objects and the only filter I use for this is a neodymium filter.

[Kronos831]

Okay! Thank you! My barlow has a

• 2) Nosepiece threaded to accept 1.25” filters  as flo states  So i should be able to put them together ,right?
• So anyway, im buying the Ts One will i be able to use my barlow and filter on it?

[Ricochet]

8 minutes ago, Kronos831 said:

Okay! Thank you! My barlow has a

• 2) Nosepiece threaded to accept 1.25” filters  as flo states  So i should be able to put them together ,right?
• So anyway, im buying the Ts One will i be able to use my barlow and filter on it?

That means that the barlow has a filter thread on the bottom of it. The thread that connects the barlow cell to the body may be the same thread of different, you will have to unscrew it to find out. In fact, looking at a picture of the barlow, I don't know if it will even unscrew. It looks like it might be a single piece.

[Kronos831]

You mean the bottom part with the lens? It unscrews easily .

[Rusted]

I have the T-S binoviewers and both TS GPC correctors. 
I do not recommend the 1.6X TS GPC because its non-standard diameter is very hard to clamp in some eyepiece fittings.
Nor does it fully compensate for the glass path length of the binoviewers.
The 2.6x GPC produces very high magnifications so I have never used it even with 40mm eyepieces.

It is a shame that the TS does not have a filter thread in the binoviewer body for direct attachment of Barlow nose pieces.
That would allow lower powers to be used. All correctors or Barlow nose pieces must be screwed into the binoviewer nosepiece.
Which causes higher amplification becase the greater distance from the eyepieces.

I recently bought the William Optics 2x Barlow nosepiece [with standard 1.25x filter thread] and much prefer it to the TS GPCs.
Others have tried different 2x Barlow nose pieces and have recommended them.
 

[Cosmic Geoff]

The binoviewers in my signature accept the active x2 barlow element unscrewed from a Skywatcher x2 Barlow.  So the same probably applies to other binoviewers that look like mine (i.e. most of the cheaper ones - all clones of each other).  The Barlows that came with the bino kit worked but were not very good.

There have been several threads on binoviewers here in the past. I recommend searching for them. 

Be aware that with Newtonians etc you will have trouble getting focus without a Barlow (etc) as you are inserting about 100mm extension into the light path and a Newtonian focuser will only give you about 20mm to play with..

[Louis D]

Not mentioned is the choice of eyepieces for binoviewer usage.  I've found that deep undercuts lead to tipped eyepiece when you tighten down the collet to secure them.  If this happens, you can either fill the undercut with pinstriping tape or simply hold the eyepiece firmly down while clamping.

Smaller diameter eyepieces are advantageous because it's easier to fit your nose between them.  My favorites when using a 2x barlow nosepiece (from a Meade 140 2x yielding 3x) to reach focus are the 23mm Vite/Svbony 62 degree aspheric eyepieces available for $10 on ebay from China.  They are more than sharp enough in the central 75% of the field and are nice and small and light (1.5 oz. each) with 17mm of usable eye relief with the rubber eye cup removed and a very shallow undercut.

Remember, the binoviewer is heavy all by itself (19 oz.), so putting two heavy eyepieces in it makes balancing it that much tougher.  Long focal length Plossls weigh around 4 to 5 ounces each.

Also keep in mind that the low cost binoviewers have a 22mm clear aperture, limiting the maximum field stop usable on eyepieces.  As a result, 32mm Plossls tend to vignette at the edges in them while 25mm/26mm Plossls do not.

I've found that eyepieces seem about 5 to 10 degrees wider in a binoviewer than in monovision.  Thus, 60 degree eyepieces seem more like 65 to 70 degree eyepieces.  I'm guessing it's something to do with your brain integrating the two images into one larger virtual image.