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Equipment Discussions >> Eyepieces

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bdcmd
sage
*****

Reged: 03/14/08

Loc: Glen Rose, Texas
Re: 32mm RKE wide angle Erfle? new [Re: Jon Isaacs]
      #4315157 - 01/14/11 10:11 PM

I dunno, but I'm not sure I want anything much sharper than a tack that close to my eye. . . . .

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Mark Swanson
member
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Reged: 03/09/07

Loc: Irving, Tx
Re: 32mm RKE wide angle Erfle? new [Re: GaryJCarter]
      #5546296 - 11/29/12 09:33 PM

I am more enamored with the eyepiece being discussed than having someone like you put your 2 cents in. I had this eyepiece for over 20 years. I had several. I sold it to try something else and then bought the Edmund back as I grew to miss it everytime. I have had 3 different Edmund 32MM Erfles. Get over it.

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Mark Swanson
member
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Reged: 03/09/07

Loc: Irving, Tx
Re: 32mm RKE wide angle Erfle? new [Re: Jon Isaacs]
      #5546315 - 11/29/12 09:45 PM

Who asked you?

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Mark Swanson
member
*****

Reged: 03/09/07

Loc: Irving, Tx
Re: 32mm RKE wide angle Erfle? new [Re: dan_h]
      #5546337 - 11/29/12 09:58 PM

You asked a dumb question, but to be "polite" I will answer it. I was finished with the review of the 31 Nagler versus the 32 Edmund. I merely pointed out some other eyepieces that I have and like.

The Brandon I used was a 32mm and I have compared it to a University 32mm 1.25" Koenig in an f14.4 Questar 3.5".

It was quite a bit sharper in the Questar than the Koenig. I also compared the Brandon to a 32mm Celestron 1.25" Erfle. Again, the Brandon was obviously sharper.

I did not compare the Koenig to the Celestron Erfle. Are you some sort of PHD eyepiece reviewer who decides what is appropriate to include in a review? Exactly what is your point, other than you are probably just another Televue suck up?


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GOLGO13
Carpal Tunnel


Reged: 11/05/05

Loc: St. Louis area
Re: 32mm RKE wide angle Erfle? new [Re: Mark Swanson]
      #5546656 - 11/30/12 04:36 AM

I don't think there was anything "polite" about your last 3 posts.

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BillP
Postmaster
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Reged: 11/26/06

Loc: Vienna, VA
Re: 32mm RKE wide angle Erfle? new [Re: jrbarnett]
      #5547091 - 11/30/12 12:18 PM

Quote:

"RKE" stands for "Rank Kellner Eyepiece". It is pretty much a standard Kellner reversed.




Rank, Kaspereit, Erfle, per filing for the RKE trademark ( click on document called UNCLASSIFIED ). Plus, when you look at a standard Kellner design it is a plano-convex doublet followed by a convex-plano singlet. And RKE is a double-convex singlet, followed by a convex-concave doublet. So both groups use different curve directions than the Kellner. When you look at the field doublet in an RKE, it is the same configuration as the field doublet in an Erfle or a Kaspereit design. The Kaspereit was developed from the Erfle. The upper 2 doublets of the Kaspereit are both double convex doublets. So the RKE is like removing one of those doublets, and replacing the other with a same curved singlet. So overall, looks much more like a hybrid of the Erfle and Kaspereit designs than it does at all like a reversed Kellner at all. The only common thing between the RKE and the Kellner is that they both are 3 elements in a 2-1 (or 1-2) configuration. The curves are all wrong between them, unlike the Erfle and Kaspereit.


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jrbarnett
Eyepiece Hooligan
*****

Reged: 02/28/06

Loc: Petaluma, CA
Re: 32mm RKE wide angle Erfle? new [Re: BillP]
      #5547123 - 11/30/12 12:34 PM

Yes, but we didn't know about that document in early 2011, and have discussed it subsequently in a different thread, after the post you're responding to.

- Jim


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Sarkikos
Postmaster
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Reged: 12/18/07

Loc: Suburban Maryland, USA
Re: 32mm RKE wide angle Erfle? [Re: jrbarnett]
      #5547136 - 11/30/12 12:42 PM

Quote:

"It is sharper on axis than any plossl, 1RPD, Proxima,etc.."




Damning with faint praise?

Mike


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Sarkikos
Postmaster
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Reged: 12/18/07

Loc: Suburban Maryland, USA
Re: 32mm RKE wide angle Erfle? new [Re: Sarkikos]
      #5547161 - 11/30/12 12:53 PM

http://www.astromart.com/articles/article.asp?article_id=793

"There is a place for all of these designs. It depends on what you want out of your set of eyepieces."

I wonder if that includes Televue designs as well?

Mike


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BillP
Postmaster
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Reged: 11/26/06

Loc: Vienna, VA
Re: 32mm RKE wide angle Erfle? new [Re: jrbarnett]
      #5547322 - 11/30/12 02:29 PM

Quote:

Yes, but we didn't know about that document in early 2011, and have discussed it subsequently in a different thread, after the post you're responding to.

- Jim




OMG...look how old that post was. My bad! I never check the dates and assume posts are relatively recent. Sorry I missed that

btw, you still have the 1 RPD? I need a pic of it


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Mark Swanson
member
*****

Reged: 03/09/07

Loc: Irving, Tx
Re: 32mm RKE wide angle Erfle? new [Re: Sarkikos]
      #5547911 - 11/30/12 09:28 PM

Yes. Televue too. I don't think that you have to pay Televue and Pentax prices to get good glass. However, I am all for free enterprise.

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Mark Swanson
member
*****

Reged: 03/09/07

Loc: Irving, Tx
Re: 32mm RKE wide angle Erfle? new [Re: BillP]
      #5547915 - 11/30/12 09:29 PM

I no longer have the 1RPD. No pics either.

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Dave Ittner
sage
*****

Reged: 05/29/12

Loc: SF Bay Area, California
Re: 32mm RKE wide angle Erfle? new [Re: Mark Swanson]
      #5548072 - 11/30/12 11:52 PM

what is the 1RPD?

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jrbarnett
Eyepiece Hooligan
*****

Reged: 02/28/06

Loc: Petaluma, CA
Re: 32mm RKE wide angle Erfle? new [Re: Dave Ittner]
      #5548111 - 12/01/12 12:24 AM

"1 revolution per day"

A rebrander of Chinese eyepieces, sold through Astrobuffet. Basically the same eyepiece as the 30mm BW Optik UWA and others from the same maker. All are clones of a Japanese eyepiece called the "Widescan III".

1rpd ST80: http://www.astrobuffet.com/ab/30mm_vert.jpg

BW Optik: http://www.cloudynights.com/classifieds/data/17/203014-1344291783bw1-large.jpg

Widescan IIIs: http://www.astromart.com/images/classifieds/358000-358999/358231-1.jpg

Agena UWA: http://agenaastro.com/media/catalog/product/cache/1/image/9df78eab33525d08d6e...

Very poor edge correction in fast scopes.

- Jim


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Dave Ittner
sage
*****

Reged: 05/29/12

Loc: SF Bay Area, California
Re: 32mm RKE wide angle Erfle? new [Re: jrbarnett]
      #5548126 - 12/01/12 12:39 AM

thanks. I learn something new every day.

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