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TS Binoviewers arrive


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Hello. I have just managed to purchase some TS Binoviewers from Derek. So thought would put a little post up. Have thought about Binoviewing for a while as I did always enjoy the two eye approach when using my binoculars ( IMO seems to shut you off from the outside world more ,and draw you into the target ).  These Binos have recently came up for sale,so I thought I would give it a go. I will probably use them mostly on lunar , but have thought about trying them on solar also as I have never tried this before ( warning for newbies, do not use your telescope to look at the sun ,as a special solar filter must be used). So should be an interesting experience overall. Any observations or advice then please reply, will use on SW equinox 120ed apo.

I will obviously need to get pair eyepieces, so please understand this if the collectionist lable is going to be used?

Thanks and I hope you like my new accusations into binoviewing. ☺   

 

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Nice set of binoviewers. They have the compression ring fittings for eyepieces which are better IMO than the normal small (and fiddly, easy to lose!) screws.

Optically, the main brands of binoviewers are much the same at this price point, eg Baader, WO, Skywatcher, Celestron etc. They are all pretty good when well collimated.

You will need an OCS (barlow lens) to bring them to focus in your ED120, did one come with the set? (sometimes they come with two, such as a x1.6 and a x2.0 or x2.5).

The great thing about bv's is that they don't need high end eyepieces to deliver great views: it's something to do with using both eyes, which compensate for each other. Also, there is a useful limit to the focal length you can use, most people accept this as around 25/26mm, as above this you will get vignetting (darkening) of the edge of field of view. This is due to the limited aperture, usually around 20mm, on the binoviewers eyepiece side.

In practice, this means that if you use a pair of 26mm plossls, with an OCS/barlow of x1.6, you will get the magnification equivalent of a 16.25mm eyepiece (26/1.6). Bear this in mind when selecting your eyepieces. I'd suggest that a pair of 25mm plossls with a pair of 15mm to give an effective focal length of 9.375 (15/1.6) will give some very nice views of the moon. These examples are based on your using a x1.6 barlow, if you use another size such as x2, you need to redo the arithmetic :-).

For interest there is a pair (or was yesterday) of WO 20m wide angle for sale for £43 posted for the pair, on UKABS. Although nothing to do with me, the seller is much respected and you could buy from him with confidence. These are the eyepieces supplied as standard with WO binoviewers and they are not bad at all.

Hope this helps, and happy binoviewing!

Dave

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I'm not sure that the Barlow lens/ binoviewer relationship is quite that straightforward. As an instance, a 2x Barlow with an eyepiece fitted will effectively halve the focal length of the eyepiece in use, this is determined by the separation of the Barlow and eyepiece. Increasing this distance results in a higher effective amplification and the increase is significant with long light path in a binoviewer. This can be avoided with a telenegative  Barlow, maybe the OCS versions are?.  :icon_biggrin:

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I have a pair of WO binoviewers (probably the same optics as they are all made by United Optics I believe) and I can just about reach focus with a 1.6 OCS in an ED120.

You have more room for error if I use a 2.0 OCS. In an ED80 scope I have to use the 2.0 OCS as I cannot reach focus with the 1.6 OCS.

I also had to buy a Baader prism (non-Zeiss) diagonal to get enough back focus to get them to work.

Hope this helps.

Tony

 

Edited by Star Struck
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Congrats on the new BV's. I did enjoy the views through the WO bino's I had but did find them a bit of a fuss to focus in my different scopes not to mention the thought of having to buy yet another set of eyepieces to use in them. I'm sure that thought appeals to many collectionists on the forum though :D 

Edited by spaceboy
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Congrats on the binoviewer! I have been very impressed with mine (same supplier, but branded Baader). I have 2x the 25mm stock Super Plossls that sometimes come dobs, and also 2x TV15mm plossls.  On my 15", I use a 2.5x Powermate to reach focus.

I find binoviewing very impressive on the Moon, planets and solar (with film on my 250px).

Happy non cyclops observing :)

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Glad to hear they arrived safe and sound :smile:

I can't help with the question of whether or not they will reach focus with the ED120 without a barlow as I never tried them in that scope, but @Stu was the previous owner of both so perhaps he knows?

I hope you enjoy them :wink:

 

Edited by DRT
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