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28mm RKE in Maxbright binos?

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#1 Chopin

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Posted 18 December 2013 - 04:34 PM

For those of you having experience with this combo, do you notice any vignetting? Or at least slight vignetting to one side if the optical paths are not perfectly centered? I see the 28RKE is listed with a 23.3mm field stop, while Baader claims the Maxbright BV to have a 23mm clear aperture. Those figures are pretty darned close, but I understand the placement of the field stop can make or break how it behaves.

#2 Vondragonnoggin

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Posted 19 December 2013 - 06:33 AM

Well, I don't have BV's, but I have a binocular telescope with clear aperture of 22mm and my pair of RKE 28mm's work great. No vignetting. Sharply defined edge. It gave me 3 degrees and 16x in my 70mm BT.

#3 Chopin

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Posted 19 December 2013 - 08:39 AM

That's a valuable answer. Thanks, Eric.

#4 R Botero

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Posted 19 December 2013 - 01:09 PM

No vignetting with my BV but I have a Mark IV.

#5 Chopin

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Posted 19 December 2013 - 04:29 PM

Thanks for the reply, Roberto.

#6 Philip Levine

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Posted 19 December 2013 - 08:31 PM

Hi Jason, I tried a set of RKE 28mm eyepieces in my MaxBright binoviewer and had difficulty with both IPD and eye relief. Maybe it was just my eyes. But I do know I had dramatically better results putting a set of Celestron 26mm Silvertops in the MaxBright.
Phil

#7 Chopin

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Posted 19 December 2013 - 08:42 PM

Hi Jason, I tried a set of RKE 28mm eyepieces in my MaxBright binoviewer and had difficulty with both IPD and eye relief. Maybe it was just my eyes. But I do know I had dramatically better results putting a set of Celestron 26mm Silvertops in the MaxBright.
Phil


Thanks Phil. When you say you had a difficult time with eye relief are you referring to holding the image?

#8 Vondragonnoggin

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Posted 19 December 2013 - 09:40 PM

Eye relief is very long in these. Stated ER is 24.5mm. If you get too close you might get blackouts. I like it myself. That particular piece has a one of a kind view. For best float effect, don't use eye cups, keep your eyes far enough away to not get blackouts and throw something over your head to block stray light or be at a dark sight. It takes a little practice, but comes easily enough. Not for everyone I guess. Enough really like it though.

#9 Jeff B

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Posted 20 December 2013 - 10:12 AM

Hi Jason, I tried a set of RKE 28mm eyepieces in my MaxBright binoviewer and had difficulty with both IPD and eye relief. Maybe it was just my eyes. But I do know I had dramatically better results putting a set of Celestron 26mm Silvertops in the MaxBright.
Phil


Thanks Phil. When you say you had a difficult time with eye relief are you referring to holding the image?


Phil's experience is similar to mine but if you're seated the 28 RKE's are a hoot. The Edmund 28 MM Plossl is noticably more "comfortable" and gives a fat slice of that floating effect without the blackouts. The old 26 & 30 MM Celestron/Vixen Silvertops are my favorite low power bino-viewer eyepieces, especially the 30 MM but good luck devloping a pair of the 30MM. The 26 MM's are pretty common and reasonnable in price ($45-55 each).

And my Smart Astro 28MM Flat Fields are wonderful as well.

So, you have plenty of choices.

Jeff

#10 Space Dragon

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Posted 20 December 2013 - 04:34 PM

Jason

I believe the front aperture in the MB is 23mm but at the EP side it is 21mm and this is what will govern the field stop.
And yes, I think the placement of the FS varies between makes to further confuse us...:-)
I found a Celestron 25mm Plossl to work well in mine without vignetting, a good binoviewer, despite the smaller prisms.

#11 Vondragonnoggin

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Posted 20 December 2013 - 04:38 PM

Jason

I believe the front aperture in the MB is 23mm but at the EP side it is 21mm and this is what will govern the field stop.
And yes, I think the placement of the FS varies between makes to further confuse us...:-)
I found a Celestron 25mm Plossl to work well in mine without vignetting, a good binoviewer, despite the smaller prisms.


This should be fine for the 28 RKE. Even a 20mm CA at eyepiece side should give good views without vignetting.

I generally don't get EP's with larger than 24.5mm field stop if using a 22mm CA binocular telescope.

I guess one can always purchase just one eyepiece to try and use it mono in a scope and try it on one side of the BV before purchasing a second one.

The 28mm RKE is outstanding mono too IMHO.

#12 Chopin

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Posted 20 December 2013 - 07:09 PM

Jason

I believe the front aperture in the MB is 23mm but at the EP side it is 21mm and this is what will govern the field stop.
And yes, I think the placement of the FS varies between makes to further confuse us...:-)
I found a Celestron 25mm Plossl to work well in mine without vignetting, a good binoviewer, despite the smaller prisms.


Cool info, Duncn. How does one make that calculation? If it's 21mm it should obviously not be an issue. Is there a standard way to "plug" the field stop into a formula, or is this a case by case basis?

EDIT: Nevermind, I just realized you are talking about the Maxbrights, not the RKE :foreheadslap: :lol:

#13 Starman81

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Posted 21 December 2013 - 02:16 AM

Phil's experience is similar to mine but if you're seated the 28 RKE's are a hoot. The Edmund 28 MM Plossl is noticably more "comfortable" and gives a fat slice of that floating effect without the blackouts.

Jeff


I agree with Jeff. Holding the view with the RKEs was tough so I switched to the Edmund Plossl 28mm's. BTW, the RKE's did not vignette in my BV'er at that time (William Optics).

#14 pftarch

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Posted 05 January 2014 - 04:04 PM

....Phil's experience is similar to mine but if you're seated the 28 RKE's are a hoot.....


The "floaty effect is cool, but tough to hold and gets tiresome. I put the included rubber boots on and it is a snap to maintain proper eye position, however, the floaty effect goes entirely away. What doesn't go away is a VERY crisp, detailed, in focus view edge to edge in my Z10 dob, and I love it. Combined with my Earthwin 6 level power switch, they are typically the only eyepieces that I use.


Peter T.

#15 Chopin

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Posted 06 January 2014 - 09:07 AM

I've been loving the Pentax 12XF's (currently my only BV pair, but I am on the verge of making the 28 RKE's happen. The feedback from you guys is appreciated highly.

That floaty effect that is often talked about, I wonder if it is similar to my old 35mm Ultima, or the old 7mm smooth top Nagler...

#16 Allan Wade

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Posted 12 January 2014 - 06:58 AM

Anyone used the 15mm RKE in any binos? That focal length I think is going to be about optimum for use with the power switch in my Denks when observing planets and lunar.






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