Lowest FL eyepice usable in Denk II binoviewer?
Posted 31 January 2013 - 04:58 PM
Posted 31 January 2013 - 05:16 PM
If you want new, and want to keep price under control, I can recommend the Vixen NPL Plossls. These come in 10mm.
I have a pair in 15mm and find them to be quite excellent and they only cost $30 new apiece.
The only serious issues with the 24mm Pans is that they will vignette pretty badly with the low power arm in. I found that even the 22mm Pans vignetted. 19mms worked fine.
Posted 31 January 2013 - 05:58 PM
I guess the vignetting of the 24 pans makes sense since the Denk aperture is 26mm and the 24 pan field stop is 27 plus there is that long path through the prisms. This wasn't an issue with the Mark V but you get what you pay for...
Do you know the largest field stop that won't vignette in the denk II? Thanks.
Posted 31 January 2013 - 06:08 PM
Posted 01 February 2013 - 09:58 AM
This was not a problem when using the system in straght through mode.
I don't know if the 24mm Pans would vignette (I think they have a 28mm field stop, but the rear port on the binoviewer is almost working as the field stop so you would not see it as vignetting, but just a slightly reduced field size).
The 22mm Pans worked great though.
So you can go with a 28mm field stop if you want, but again, since the rear aperture of the bino really becomes the field stop, there isn't much point in it.
And if you want the lowest power, you can get that with a 40mm Plossl.
I am using my 40mm and 32mm Plossls as much (or more) as my 24mm widefields. I like the brighter view. And both of these would be fine in the Denkmeiers because both have field stops very close to the end of the barrel, so once again, the rear opening of the prism housing really becomes the field stop.
Posted 01 February 2013 - 11:49 PM
I have not tried Baader orthos but from what I have read, they are comparable to UO orthos (at least the old ones were). Another consideration might be the TMB planetary II series, which have better eye relief than the orthos and are still on sale for $40 at astronomics.com . Have not looked through those but read many good comments. They will maybe not be quite as crisp as the orthos. The Pentax are over the price limit you mentioned ( I have seen them for $140 from Pentax through Amazon.com).
Posted 02 February 2013 - 12:21 AM
...but you get what you pay for...
No, YOU got what YOU paid for.
If ya DON'T get what you paid for, you file charges.
Do you know the largest field stop that won't vignette in the denk II?
Don't know the measured FS value, but i've finally settled on the Vixen 22-LVWs. Probably very similar specs to the Denk 21mm EPs... they seem to work swimmingly in the Denks! All modes. No vignetting seen.
When i ran Pan-24's in the Denk, in an SCT, they vignetted noticeably in "reduction" mode. When i switched to using a Dob, the vignetting diminished greatly... tho was still there a bit.
However, the eye-relief on the Pans was pretty atrocious, and i didn't much care for their PC distortion... the Vixens stomp the Pans in pretty much every regard, especially for the Denks.
Thank heavens i did *NOT* get what i paid for... i got far more! The Vixens cost much less than the Pans, and suit my needs far better!
Posted 02 February 2013 - 08:30 AM
Posted 02 February 2013 - 01:18 PM