Moonglum
professor emeritus
Reged: 06/01/08
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Max FoV in Denk2 options?
#4282041 - 12/31/10 09:19 AM
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With no vignetting. Looking for user experience with TV 32 plossls, 24 Pans, 31 Tak LE's, hm, what else...28 RKE's. Suggestions welcome for discontinued eyepieces. I'm after Max FoV with best contrast. In other words, I'd be willing to give up a bit of field for superior contrast. The Brandon 24's are sold out, the 32's sound like too much ER and mine is a F7 apo anyways...
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Mike B
Starstruck
Reged: 04/06/05
Loc: shake, rattle, & roll, CA
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Re: Max FoV in Denk2 options?
[Re: Moonglum]
#4282471 - 12/31/10 12:36 PM
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Using my Denk II, i found 24mm Pans vignetted a noticeable amount, but i never found it "objectionable"... some do. Amazingly, some don't even seem to notice it at all- am not sure what's up with that. Perhaps a YMMV thing?
I have an older pair of Meade 24.5mm SWA's that seem to do quite a bit better in that regard. Another nice match for the Denk is a set of old Nikon microscope EPs- they're about 50* jobs, so there's maybe a little FoV left on the table?
Never tried, but always wanted to were Vixen 22mm LVWs, Pentax 21mm XLs & 20mm XWs, and Denk's own D21's. That Denk itself mates a 21mm 65* EP to their system tells you where THEY think its optimised. 
Another option that has floated around the field quite a while is the old 20mm 84* 'Widescan' EP- not so well corrected around the edges, but in an F7 'fractor might be just the ticket? I tried them in a friends scope once... nice enough for view, but a bit short on ER for my tastes (wearing eyeglasses). He sold them back into the collective soon after acquiring 'em... he's a Nagler/Ethos kinda guy, and these didn't quite butter his bread. 
Otherwise, your 28mm RKE idea may be a very good one. I know another CNer who used such a pair in his Denk, but i suspect he may've eventually sold them off. But i think he was generally pleased with them.
Happy hunting!
 mike b
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jack45
Post Laureate
Reged: 07/07/03
Loc: Lacey WA
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Re: Max FoV in Denk2 options?
[Re: Moonglum]
#4282489 - 12/31/10 12:44 PM
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How about the Orion Ultrascopic eps,25mm,30mm and 35mm. Not sure about superior contrast but should be up there with the rest.
Clear Skies!
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bcuddihee
Carpal Tunnel
Reged: 11/04/06
Loc: Cincinnati Ohio
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Re: Max FoV in Denk2 options?
[Re: jack45]
#4282631 - 12/31/10 01:33 PM
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One of the best...most contrast views of m42 was with a pair of 28 rke's. The long er takes a bit to get accustomed to, but when you do it's like magic. It doesn't get much better.
The volcano top design and the lack of undercuts just add to an already fantastic view. If any bino ep comes close to producing a 3-d view the 28 rke's are the best IMO at this. I am hoping the 24 Brandons I just purchased will be even better in this regard. Skies here are supposed to be clear here Sunday evening. I'll be checking the Brandons out then.
bc
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Moonglum
professor emeritus
Reged: 06/01/08
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Re: Max FoV in Denk2 options?
[Re: bcuddihee]
#4282674 - 12/31/10 01:55 PM
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Mike, wish someone would comment on the LVW's...
Jack, I seem to remember someone saying the Ultrascopic 30" vignetted in one of the main bino brands.
Bri., the RKE's are a must for their pricing and uniqueness.
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Tamiji Homma
Carpal Tunnel
Reged: 02/24/07
Loc: California, USA
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Re: Max FoV in Denk2 options?
[Re: Mike B]
#4282692 - 12/31/10 02:00 PM
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I think Mike has a point "i never found it objectionable." with Panoptic 24 with Denk II.
Yes, you can see it if you are looking for it. Well, I learned to ignore it, not to be bothered by it too much. I hope you look at center more than edge 
It is more important to be able to focus to infinity without OCA to gain wider TFOV. I did experiment with a few eyepieces.
field stop measured by TFOV using TV 32 as reference.
21.2mm Pano 19
23.2mm RKE 28
24.9mm Siebert Ultra 28
26.4mm Takahashi LE 30
26.9mm Televue Plossl 32
27.1mm Panoptic 24
29.1mm Ultrascopic 35
31.0mm Hyperion 31 with 1.25" nosepiece
I usually notice (bit bothering) vignetting when binoviewer clear aperture is 2mm smaller than eyepiece field stop. When eyepiece AFOV is large, I notice less vignetting than smaller AFOV eyepiece with similar field stop. I guess wide AFOV makes lesser visibility to edge than with small AFOV eyepiece.
I like LE 30 best, by the way.
Tammy
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Mike B
Starstruck
Reged: 04/06/05
Loc: shake, rattle, & roll, CA
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Re: Max FoV in Denk2 options?
[Re: Moonglum]
#4283049 - 12/31/10 04:52 PM
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Mike, wish someone would comment on the LVW's...
Okay... but i can only do so for the 17mm of the species.
I absolutely LOVE them! Many pairs have come & gone from my EP case, but these are CDF's... to be pried from my Cold Dead Fingers! They are brutally sharp clear to the fieldstop, have excellent transmission as far as i can see it, are ergonomically VERY comfortable- so as to be practically invisible during use. I've come very close a couple of times to hot-gluing them into the BVer & selling everything else off!  
My main regret is that i failed to pursue a pair of 22mm's back when they were readily available for MUCH less than their current ~$290 pricetag (each!  )
Tammy's raw-number analysis really nails the matter pretty well! Thanks for posting that... have you measured any others?
 mike b
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Moonglum
professor emeritus
Reged: 06/01/08
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Re: Max FoV in Denk2 options?
[Re: Mike B]
#4283418 - 12/31/10 07:38 PM
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Tammy, your vouch for the Tak LE30 carries considerable wieght. You never tried any of the LVW's?
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Tamiji Homma
Carpal Tunnel
Reged: 02/24/07
Loc: California, USA
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Re: Max FoV in Denk2 options?
[Re: Moonglum]
#4283705 - 12/31/10 09:58 PM
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Tammy, your vouch for the Tak LE30 carries considerable wieght. You never tried any of the LVW's?
Ha ha ha. LE 30 isn't that heavy I've tried LVW 22 on Vixen Binoculars once during daytime so I can't comment on performance under night sky. Other LVW that I have tried is LVW 42. It isn't for binoviewer. I remembered that some people didn't like LVW 42 performance but I like it very much on my long focal length scope (3000mm f/11.5). It may not have XW 40 edge performance but it is quite comfortable to look through.
If you give up vignetting free and can cope with longer eye relief (25mm-ish), Ultrascopic 35 is quite nice with f/7 scope when you need bright image.
Tammy
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Tamiji Homma
Carpal Tunnel
Reged: 02/24/07
Loc: California, USA
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Re: Max FoV in Denk2 options?
[Re: Mike B]
#4283716 - 12/31/10 10:04 PM
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Tammy's raw-number analysis really nails the matter pretty well! Thanks for posting that... have you measured any others?
Here you go:
Field stop in millimeter, focal length of eyepiece, and eyepiece name.
2.5 3.0 Televue NZ 3
2.6 3.6 Takahashi LE 3.6
3.0 4.0 ZAO II 4
3.3 4.0 Televue NZ 4
3.7 7.0 TMB Supermonocentric 7
3.8 5.1 Pentax XO 5
4.2 5.0 Televue NZ 5
4.3 3.5 Pentax XW 3.5
4.4 6.0 ZAO II 6
4.7 5.0 Takahashi LE 5
5.1 6.0 Televue NZ 6
5.3 5.0 Radian 5
6.2 5.0 Pentax XW 5
7.0 7.5 Takahashi LE 7.5
7.1 3.7 Ethos SX 3.7
7.3 10.0 ZAO II 10
8.9 7.0 Nikon NAV SW 7
8.9 11.0 Televue Plossl 11
11.0 12.5 Takahashi LE 12.5
11.6 16.0 ZAO II 16
12.4 15.0 Televue Plossl 15
12.5 8.8 Leica 50x-8.8
12.6 10.0 Pentax XW 10
12.9 12.0 Pentax XF 12
13.7 11.0 Leica 40x-11.0
13.8 8.0 Ethos 8
16.0 14.7 Leica 30x-14.7
17.6 14.0 Nikon NAV SW 14
17.8 14.5 Denkmeier 14*
18.0 18.0 Radian 18
18.1 17.6 Leica 25x-17.6
19.2 12.5 Docter UWA 12.5
21.2 16.0 William Optics UWAN 16
21.2 19.0 Televue Panoptic 19
22.0 17.5 Nikon NAV SW 17.5
23.2 28.0 RKE 28
24.0 20.0 Pentax XW 20
24.4 21.0 Denkmeier 21
24.4 25.0 Zeiss 25
24.5 21.0 Denkmeier 21
24.6 14.0 NAV HW 17-EiC-14
25.0 28.0 Siebert Ultra 28
26.3 30.0 Tak LE 30
26.4 30.0 Takahashi LE 30
26.9 32.0 Televue Plossl 32 T2
27.1 24.0 Televue Panoptic 24
28.5 24.0 Hyperion 24
29.1 35.0 Ultrascopic 35
29.6 17.0 Ethos 17
30.0 17.0 NAV HW 17
31.0 22.0 Nagler 22T4
31.1 31.0 Hyperion 31-1.25 T2
35.0 31.0 Hyperion 31-2 T2
35.5 30.0 Paragon 30
36.3 30.0 Pentax XW 30
37.9 31.0 Hyperion 31
38.6 28.0 William Optics UWAN 28
40.8 30.0 BW-Optik/Zeiss-30
41.5 32.0 RKE Wide Angle Erfle Eyepiece 32
43.0 50.0 Takahashi LE 50
45.9 40.0 Paragon 40
46.4 40.0 Pentax XW 40
46.6 42.0 Vixen LVW 42
*) Denk 14 appears to be 14.5mm than 14mm
Tammy
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Moonglum
professor emeritus
Reged: 06/01/08
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Re: Max FoV in Denk2 options?
[Re: Tamiji Homma]
#4284388 - 01/01/11 10:21 AM
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The Takahashi LE 30 and the Tak LE 30 are different generation? Which is better?
_-it's kind of you to let us pick your brain a bit, and Happy New year.
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Tamiji Homma
Carpal Tunnel
Reged: 02/24/07
Loc: California, USA
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Re: Max FoV in Denk2 options?
[Re: Moonglum]
#4284397 - 01/01/11 10:27 AM
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The Takahashi LE 30 and the Tak LE 30 are different generation? Which is better?
_-it's kind of you to let us pick your brain a bit, and Happy New year.
Oh, that's the same eyepiece. I made multiple measurements for last few years, they are duplicated result that I should have removed
Tammy
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