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Was going to nab new RKEs to complete my set and..

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#26 bremms

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Posted 27 January 2013 - 12:35 PM

There is one of the old ones( 79.00??) and a "real" RKE on the bay right now. $79.00 is wayyyy to much for the old Carton. A newer RKE or circle NJ 32mm TV plossl will be better

#27 refasali

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Posted 27 January 2013 - 01:05 PM

from the same catalog, just opposite the eps in question
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#28 actionhac

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Posted 27 January 2013 - 01:47 PM

A traditional standard Kellner has a doublet eye lens and a singlet field lens.
The RKE (Rank Kellner Eyepiece) appears to be the reverse of above and the elements are modified.
Also Type 2 and 3 Kellners exist.
The old version of the Edmund 28mm (1 1/8") could be one of these type 2 or 3 Kellner variations, whatever they are like, but 2 doublets doesn't seen to fit the Kellner profile does it, but in fact the 2 doublets may possess some technical/design feature that allows it to remain a Kellner, sort of like poor Pluto, a dwarf, but still a planet.
They may be something cooked up for the military, I think we should look into the Type 2 and 3 Kellner.

RKE cutaway:
http://www.handprint...2.html#eyeterms

Robert

#29 rdandrea

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Posted 27 January 2013 - 01:53 PM

Type III Kellner is discussed here:
http://www.cloudynig...wflat.php/Cat/1,2,3,4,5,6,7,8,9,10,11/Number/5204908/Main/5202111

#30 refasali

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Posted 27 January 2013 - 05:33 PM

Ah- there's a Kellner type I, II, III mention in the old Edmund optical books... I the believe the following is from All About Telescopes (1975)
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#31 actionhac

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Posted 27 January 2013 - 07:53 PM

That book is a masterpiece.



#32 orion61

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Posted 27 January 2013 - 11:37 PM

You need to take your time and find the right eye placement then they're very sweet.


I could not have stated it any better! It always takes a second or two to get your eye placement just right with that eyepiece. I enjoy the views with mine.


I love my set of RKE"s! Only bad thing about using the
28 is there is so much eye relief I have trouble using it in the City with street lamps, I use an eye cup, The image does seem to float in front of your eyes.
I use them as my main eyepieces and am not ashamed to say so!
You do have to keep bottom covers on to keep dust off the bottom lens cause it will drive you cray with the spots!
I love the 15, 12, and 8 mm in my Bino Viewer.
I cut my teeth on small field eyepieces so I don't need the 80 degree AFOV. They are very very bright and sharp in the center of the field.

#33 Jaimo!

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Posted 28 January 2013 - 07:25 PM

The Pre-RKE's are actually asymmetrical Plössls similar to Clave's, and I find I prefer the Pre-RKE views over the RKE:

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I was even able to snag a 1" version on the bay, it has the same lens arrangement as the 1 1/8"

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Jaimo!






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