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Binoviewers

Posted: Thu Dec 07, 2017 2:43 am
by FrankPorter
Do you use a binoviewer on your Lunt 60mm or other Lunt solar scope? Is there enough back focus? As it is I have to pull the diagonal out about 1 inch to focus my Baader zoom. It would seem there is enough back focus but I'm new at this.
What binoviewers do you like best?

Re: Binoviewers

Posted: Thu Dec 07, 2017 6:23 am
by marktownley
Sorry, don't use them. Lots of people do though...

Re: Binoviewers

Posted: Thu Dec 07, 2017 6:44 am
by FlankerOneTwo
I do on occasion with the LS80, honestly spend more of my time trying to get the hang of imaging and processing. I couldn't quite reach focus straight through, but Harry Siebert makes optical correctors that will allow you to reach focus (including a 0X). A Barlow that increases outward focus requirements might work as well, I've heard that the GSO 2X does this. I bought a pair of pre-owned Denkmeier Standards that had one included, and have since acquired a "supercharged" Zeiss bino from Denis Levatić (might be on this board, I came across him on Cloudy Nights though) which is the bomb.

-Patrick

Re: Binoviewers

Posted: Mon Feb 19, 2018 10:57 pm
by Christopher
I too acquired a pair of the supercharged Zeiss binoviewers (second-second hand) a few weeks back and had a chance on Sunday through hazy skies to really give em a workout on my Lunt LS100THa and I must say I'm quite taken with the results for surface details. They came with a Baader GC 1.25 and I had a Baader GC 1.7 but neither could bring them to focus. So I omitted the GC and went with a 2X Coronado Barlow and was off to the races. I preferred a pair of University 24mm Konigs out of the eyepieces I tried. With the 2X Barlow they allowed me an FOV of roughly 2/3 of the solar disk. I'm sure that the solar minimum will afford us even more underwhelming features, but Sunday's disk was quite bland. No remarkable features on the surface and no significant prominences in terms of brightness or size. No matter, I was interested in testing the optics more than anything. Here, there was no disappointment. I found these very comfortable to look through with a bright clear perfectly collimated image. Individual diopters on both eyepieces let me dial in perfect focus. The seeing was mostly bad with a continuous thin cloud layer to contend with. But I must say that when the seeing was "in" the surface details were far superior to anything I had experienced with mono vision. It was interesting to actually observe the effects of seeing on surface detail. The phenomenon is quite different than that for prominences. Proms are visible during turbulence while the solar surface simply goes blank. I'm still pretty new to this scope and I hadn't completely figured out all it's limitations and the visual cause and effect phenomena. But with the binoviewers when it was steady the contrast was improved to the point where I could even make out some of the finer patterns on the surface which give it that wind blown grass look. I'm sold. Next I think I'm going to try and double up on a 1.25 40mm ScopeTronix eyepiece I have to gain a full disk view.

Re: Binoviewers

Posted: Mon Feb 19, 2018 11:16 pm
by Ibbo
I swapped my focuser (old JMI I had arround)and can use the binoviewers with my 60 but, as others do I mainly do imaging

Re: Binoviewers

Posted: Tue Feb 20, 2018 8:08 am
by marktownley
I know what you mean about (lack of) surface detail and bad seeing on a blank sun Christopher.

Re: Binoviewers

Posted: Wed Feb 21, 2018 3:39 am
by Valery
Christopher wrote: Mon Feb 19, 2018 10:57 pm But I must say that when the seeing was "in" the surface details were far superior to anything I had experienced with mono vision. It was interesting to actually observe the effects of seeing on surface detail. The phenomenon is quite different than that for prominences. Proms are visible during turbulence while the solar surface simply goes blank.
The cure for this: very narrow ( 0,3A o narrower) single stack etalon or better a double stacked wider etalons. Also a black cloth helps to cover from a direct sun ligh and rise the eye sensitivity.
And a binoviewer is a MUST HAVE for seeing surface details!

I must to admit that the difference between the visibility of the sun surface details in a 0,4A etalon and in a 0,25A one is really huge!