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binoviewing question

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#1 ncfo

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Posted 28 January 2013 - 12:06 PM

I have a Lunt 60/50ds and it shows me good surface detail and proms but when I use my binoviewer(Celestron binocular viewer+1.6X barlow+Celestron X-Cel 25mm), I can barely see proms. When double stacked it's even worse. It's too dim to see.
Is this becauce of its 60mm apature? Would there be improvement if I move to 80t or 100t?

#2 CarlDD

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Posted 28 January 2013 - 01:02 PM

Hi NCFO
I dont think it's the aperture, before I got my SM 90mm I used and binoviewed with an SM40, it was ok.

Whats the brightness like with just an eyepiece in the diagonal.

BR

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#3 Bill Cowles

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Posted 28 January 2013 - 03:11 PM

I just about use bino's all the time, and the image is dimmer, but I just use lower power. I even Tri-stack, and the image is unusable just a much smaller sweat spot and a dimmer image. Larger apeture would help, but I don't find it that much of a problem with my Lunt 60DS.

Bill

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#4 ncfo

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Posted 28 January 2013 - 08:30 PM

Hi Carl.
Thanks for your comment. Maybe it's because of my celestron binoviewer.

#5 ncfo

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Posted 28 January 2013 - 08:40 PM

Hi Bill.
Can you see proms with your bino's? I could see surface detail but couldn't find proms so I have to take bino's out to see proms.

#6 Bill Cowles

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Posted 29 January 2013 - 11:19 AM

Yes, and very thin and faint streamers. My main reason for bino's is the reduction of floaters, wider field and improved contrast. I have a friend with a 60DS and he always uses his scope with Denk bino's and we both agree, that Solar viewing with bino's is the only way to go. Here is a shot of him taken during last years Annular eclipse from Newcastle Utah, center line, also viewing with a Solar vest, that we both use and recommend. :cool:

Bill

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#7 Bill Cowles

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Posted 29 January 2013 - 11:35 AM

Are you tuning the scope, with my PT, sometimes edge detail will be missing until I do some tuning. If you can see proms. without the bino's then adding bino's and they are missing, I would look at the bino's, you should see them if you can see them in mono. I'm using 21's with and OCS that I use around 2X, so your eyepieces are fine. Here is another of my Solar setups, a TV Genesis, stacked with my Lunt 50mm filter and an old 60mm Coronado filter and my Denk bino's, amazing views, just hard too reach the tuning wheels.

Bill

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#8 George9

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Posted 30 January 2013 - 06:59 PM

My Denk II's have always shown proms in both my current LS80 SS and DS and my old Coronado 60 SS and DS. They are brightest at low power, but visible all the way up.

I bet it is due to vignetting. The binoviewer is probably forcing you to push the blocking filter (perhaps a 6mm) all the way forward to come to focus so that the BF is stopping the scope down to a 25mm or something.

Try an experiment. Bring the scope to focus with the binoviewer. Remove the binoviewer but leave the focuser where it is. Rig up something, perhaps rolled cardboard to bring the eyepiece to focus without moving the focuser (ie, you will have to hold the eyepiece away from the BF to come to focus). See if it looks as terrible.

Or else just note where the blocking filter comes to focus with the binoviewer, remove it, and by projecting on a white card, see how big the sun is at the point where the BF sits.

Other thoughts: a sweet spot issue? E.g., if you center the rim of the sun, do they appear?

The power seems reasonable (25mm/1.6 in an LS60).

Is this a tilt or PT LS60? PT would surprise me, but I wonder if there is some odd thing about the tilt plus the Barlow plus the blocking filter narrowing the sweet spot.

Also, did you try the 25mm eyepiece plus the Barlow without the binoviewer?

Is it possible that the binoviewer has poor transmission in red? I guess a white object should look bluish then.

George

#9 RGM

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Posted 31 January 2013 - 06:37 AM

George made a great observation, are you using a B600 or B1200. The B600 is likely the cause if that is what you have.






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