Binoviewer first light

[David Levi]

It has taken me about 2 weeks of testing to finally get first light with my TS Optics binoviewers (the cheaper ones). The preparation has been quite involved.

I bought a 2" to 1.25" compression ring adapter which enables me to remove the standard eyepiece adapter and gain some back focus. On inserting the binoviewers into the new adapter there was not enough outward focuser travel to achieve focus. If I used the original supplied eyepiece holder then there wasn't enough inward travel to achieve focus. I commandeered the Barlow lens from my 2x Barlow and with this fitted to the binoviewer nosepiece I was able to get focus with the standard 1.25" eyepiece holder. However, on testing the magnification with this set up I determined that the Barlow lens was giving me something like 3.2x magnification. I didn't find this very satisfactory and so I decided to purchase the 1.6x gpc (glass path corrector) to fit to the binoviewers. I guessed from my tests that I would be able to achieve focus with this together with the compression ring adapter. This turned out to be case. I checked this with the single eyepieces that I have and then bought a pair of 12.5mm Fujiyama HD orthoscopic eyepieces which together with the gpc will give me 128x magnification.

Excitedly I set up the telescope with the binoviewers and aimed at Jupiter. The view was immediately pleasing. The GRS was at it's meridian and showing a lovely orange/red colour. I fine tuned the distance between the binoviewer eyepieces and the individual eyepiece focusers. The experience of using the binoviewers felt very natural and easier than monocular viewing. I have always found closing one eye to be quite a strain and now with both eyes open it was much easier and more comfortable to discern details in the belts of Jupiter. The NEB was quite dark compared to the SEB. There was a nice pencil line band just to the south of the GRS. The Fujiyama eyepieces seem to give as much detail and clarity as my Televue and Pentax eyepieces. The only drawback is that with a 42° aFOV you have to use the slow motion controls a lot more often to keep the object in view. On the plus side, sharing the light between two eyes makes Jupiter appear less bright and therefore easier to look at.

The only other objective of the session was to find a double star to see how the binoviewers performed on this type of target. Looking up at the sky Arcturus was obvious and I knew that just up from it is the double star Izar. I didn't know quite what to expect with only 128x magnification as I don't think that I have ever split it with anything less than 166x magnification. The two stars were easily visible with the only binocular magnification that I had at my disposal. Not only that but for the first time ever I could see colour in the pair of stars. The brighter star was yellow in appearance and it's smaller companion was blue. I was really pleased to see these colours as I was not expecting it. I thought that the binocular view might make splitting the pair easier but I didn't think about the effect of the orthoscopic eyepieces on colour. Now that I think about it, is it the eyepieces, the binocular vision or a combination of both that has brought colour to this binary star for me? I obviously need to look at Izar with one of the orthoscopic eyepieces. I didn't think of it at the time.

Anyway, I'm very pleased with my new binoviewers and look forward to using then as much as possible. I'll have to build up a new collection of eyepiece pairs to use in them.

[domstar]

Thanks for that. A great report and really informative.

[Littleguy80]

Great report, David! If you were coming from viewing Jupiter then your eyes wouldn’t be dark adapted as it’s so bright. As a result, the cones (colour receptors) in your eyes would have still been active allowing you to see colour when you looked at Izar (Spot the guy who’s been reading about eyes recently  )

[David Levi]

Excellent info Neil @Littleguy80. I'll look out for that effect some more. Thanks.

[laudropb]

Very helpful post. I an trying to achieve focus with a new set of WO binoviewers. So far without success, but your post has given me food for thought.