Posted 12 October 2013 - 08:33 AM
I can reach focus in my 5" Istar without an OCS, and I do not use the reduction mode, just straight through. The binoviewer is wonderful to use, BUT..., it does not provide as pin-point stars as mono viewing does. The stars are just "mushy" enough to bother me.
Thinking about upgrading to something better. Are there any binoviewers that do not degrade the star image? I am looking to retain the "diamond dust on velvet" view.
Posted 12 October 2013 - 09:39 AM
Posted 12 October 2013 - 09:53 AM
But often, when I am using the same magnifications in both modes, I am able to resolve more in bino mode, and that can make the seeing more noticeable. The solution is to lower the magnification a bit, usually to 70% of mono mode. This provides me with the same level of brightness and detail as in mono, but with increased contrast, due to the binocular vision, and lowers the seeing sensitivity.
Posted 12 October 2013 - 12:00 PM
Observing under the jet stream is something I have to deal with. I will take more time, over more nights, and try to nail down if the seeing has more of an impact on the binos than on mono viewing. Maybe under good/rare/great conditions the binos will deliver the views I am after.
Posted 12 October 2013 - 01:35 PM
Posted 12 October 2013 - 01:52 PM
At 6-10X, this test is more sensitive to optical error in the BV than during normal use on the scope. You are utilizing the *full aperture* of *all* surfaces for every image point in the field. If the BV imposed, say, a 1/2 wave error, at 6X this would appear as though it were 3 waves. If the view with the BV in place is not noticeably inferior to the masked down view without, the BV is likely not at fault.
Naturally, do this test through both sides, aiming through the eyepiece barrels. And for curiosity's sake you could flip the BV around, aiming into the front barrel. You will have two overlapping images, for which very distant lights or stars (e.g., the Pleiades) would make a better target.
Posted 12 October 2013 - 02:24 PM
I had completely forgot about that test. The Moon makes an excellent target for it. By masking one half of the bino, you can check for image quality, and by using both halves, you can check for image merging. I use an 8x30 finderscope. By using the Moon, which is close to 30' in diameter, you can estimate the prism misalignment.
Posted 12 October 2013 - 07:31 PM
The one noticeable difference is the extra comfort of using two eyes, especially trying to pick out fine detail.
I haven't used my WO set for a little while; they seem very good too but with a bit less contrast, probably due to lesser baffling inside the bino.
Posted 13 October 2013 - 08:37 AM
Posted 13 October 2013 - 09:06 AM
Over the past year I have switched my mono eyepiece collection to long eyerelief because of my 60 year old eyes. I now use Panoptics and XWs for all mono viewing with my eyeglasses and this has greatly improved the quality of the view.
In bino, I am still viewing without eyeglasses, beacause of the limited eyerelief of my bino eyepiece collection. Last night I tried bino viewing with glasses at the expense of a smaller FOV, but immediately noticed an improvement. The views were in fact similar to mono.
So, it looks like my 19Pans and 13T6s will have to be replaced with 20mm eyerelief alternatives. I will start a separate thread to address this question.