Telescope Reviews: A really F-U-N eyepiece! My new 28mm RKE!

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Equipment Discussions >> Eyepieces

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leonard
scholastic sledgehammer

Reged: 10/19/07

Loc: West Virginia

Re: A really F-U-N eyepiece! My new 28mm RKE! new

[Re: Sarkikos]
#5094118 - 02/27/12 02:21 PM

Hello Mike ,

>>>>> have noticed from the RKE 28mm when Barlowed, is that the already ample eye relief is increased even more. <<<<<

How much more would you guess Mike ???

Leonard

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Sarkikos
Postmaster

Reged: 12/18/07

Loc: Suburban Maryland, USA

Re: A really F-U-N eyepiece! My new 28mm RKE! new

[Re: leonard]
#5094134 - 02/27/12 02:29 PM

Well, the native eye relief is about 25mm. IMO & IME, that might already be too much for an observation site challenged by ambient glare.

Mike

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leonard
scholastic sledgehammer

Reged: 10/19/07

Loc: West Virginia

Re: A really F-U-N eyepiece! My new 28mm RKE! new

[Re: BillP]
#5094154 - 02/27/12 02:40 PM

Hi BillP ,

Bill I need your help , I have never owned a barlow lens . What I need is a good guess as to the shift in focus position between the un-barlowed 28mm and the position with a barlow in the focuser . In other words do you need to out focus or in focus much with a barlow ????????

One more if you will , With a 2X barlow and the 28mm , how much eye relief increase do you see ????

Thanks , Leonard

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Sarkikos
Postmaster

Reged: 12/18/07

Loc: Suburban Maryland, USA

Re: A really F-U-N eyepiece! My new 28mm RKE! new

[Re: leonard]
#5094182 - 02/27/12 02:52 PM

Leonard,

I found another thread on CN that might answer your question. According to a poster on that thread, "Barlowed eye relief growth goes up as a function of the square of the eyepieces focal length." I assume this applies to a 2x Barlow. Judging from other verbiage in that thread, the effective eye relief for the RKE 28.7mm with a 2x Barlow might be about 30mm? (I wish he would have just given a formula!)

Pentax XW 7mm + Televue 2x barlow question

Mike

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amicus sidera
Carpal Tunnel

Reged: 10/14/11

Loc: East of the Sun, West of the M...

Re: A really F-U-N eyepiece! My new 28mm RKE! new

[Re: Sarkikos]
#5094222 - 02/27/12 03:17 PM

On a note related to the 28mm RKE, the rubber eyeguard that Edmund supplies with it is available as a separate item, part no. NT-60-100, listed as "Style B" on this page from their website, reasonably priced at $10.95 each. In the past I have used these eyeguards on similarly-sized eyepieces from other manufacturers, such as the Meade and TeleVue 26mm Plossls.

As noted in the comments immediately above this post, use of a Barlow lens can increase eye relief considerably, and these eyeguards are a great help in keeping one's eye at the proper distance from the eyelens when such an arrangement is used.

Also available on that page is a similar eyeguard, for use with .965" diameter eyepieces... classic refractor owners take note!

Additionally, please note that these eyeguards contain natural latex, which is an allergen for some.

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ErnieM
Pooh-Bah

Reged: 06/13/04

Loc: Phoenix,AZ

Re: A really F-U-N eyepiece! My new 28mm RKE! new

[Re: amicus sidera]
#5095069 - 02/27/12 11:52 PM

I just ordered this 28mm for use on my R130sf and ST80mm.Probably will not get much use on my Dob since my 27Pan will still be the workhorse on it.

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coopman
Carpal Tunnel

Reged: 04/23/06

Loc: South Louisiana

Re: A really F-U-N eyepiece! My new 28mm RKE! new

[Re: ErnieM]
#5095286 - 02/28/12 08:06 AM

I just ordered one this morning. Darn you guys forcing me to spend more money!

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leonard
scholastic sledgehammer

Reged: 10/19/07

Loc: West Virginia

Re: A really F-U-N eyepiece! My new 28mm RKE! new

[Re: Sarkikos]
#5095301 - 02/28/12 08:23 AM

Hi Mike ,

Thanks for the thread link , it shows the 28mm's ER increase will be on the longer side .

Thank You , Leonard

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ckwastro
Pooh-Bah

Reged: 11/23/05

Loc: Tempe, AZ

Re: A really F-U-N eyepiece! My new 28mm RKE! new

[Re: leonard]
#5095974 - 02/28/12 03:10 PM

My pair arrived yesterday. Of course there were the typical weather issues with new equipment. It was clear until about 10, but with a 140mph Jet Stream overhead and surface winds gusting to 40mph. Figured I'd wait on first-light for these.

Clouds rolled in later anyway with the fast-moving cold front.

Having said that, they are neat looking eyepieces with perhaps the largest eye-lens I've seen on a standard 1.25" EP. (The TV 1.25"/2" format Naglers are of course a different story). Looking forward to seeing what the RKEs can do.

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mmclure
professor emeritus

Reged: 12/30/10

Loc: Sacramento, CA USA

Re: A really F-U-N eyepiece! My new 28mm RKE! new

[Re: ckwastro]
#5096089 - 02/28/12 04:22 PM

My 28mm RKE (with attached Astroscan) arrived yesterday. Boy is that eyelens big! The view through the 28mm and the Astroscan was great during the day through the window of my office, and first light on the moon last night was just as impressive.

Pictures of the eyepiece will be coming, since it's a pre red stripe version.

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Crow Haven
Pooh-Bah

Reged: 01/09/09

Loc: Betwixt and Between

Re: A really F-U-N eyepiece! My new 28mm RKE! new

[Re: mmclure]
#5096280 - 02/28/12 06:17 PM

I ordered the 28 RKE on the 20th -- it was stated "in stock" -- so hopefully it won't be too much longer before I get to try it out. It sounds like a fun eyepiece and I'll enjoy comparing its view with an old Japanese Celestron 26mm silvertop plossl I've hung onto all these years.

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coopman
Carpal Tunnel

Reged: 04/23/06

Loc: South Louisiana

Re: A really F-U-N eyepiece! My new 28mm RKE! new

[Re: Crow Haven]
#5096601 - 02/28/12 09:39 PM

Mine shipped today, so that's excellent customer service!

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ErnieM
Pooh-Bah

Reged: 06/13/04

Loc: Phoenix,AZ

Re: A really F-U-N eyepiece! My new 28mm RKE! new

[Re: coopman]
#5096712 - 02/28/12 11:02 PM

Ordered mine last night,shipped today.Should be here by this weekend.Now i will see what all the fuss and meltdowns are all about.I looked at these years ago and never gave them a second thought until this thread came about.

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Ain Soph Aur
sage

Reged: 08/11/11

Loc: West Tennessee

Re: A really F-U-N eyepiece! My new 28mm RKE! new

[Re: ErnieM]
#5096819 - 02/29/12 12:27 AM

The web site shows them to be in stock, so I ordered one this evening. Looking forward to trying this one out with my soon to be finished Carton 100/1300 build!

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Rick Woods
Postmaster

Reged: 01/27/05

Loc: Inner Solar System

Re: A really F-U-N eyepiece! My new 28mm RKE! new

[Re: Ain Soph Aur]
#5096872 - 02/29/12 01:48 AM

My pair came yesterday. They're very nice looking, good fit and finish. I won't be able to try them until this weekend, though.

FWIW, the lens caps that come with Brandons (two sizes, the top one slightly bigger than the other) fit them perfectly. I just happened to have enough spares, so I'm all set.

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Ain Soph Aur
sage

Reged: 08/11/11

Loc: West Tennessee

Re: A really F-U-N eyepiece! My new 28mm RKE! new

[Re: Ain Soph Aur]
#5097087 - 02/29/12 08:34 AM

Quote:

The web site shows them to be in stock, so I ordered one this evening. Looking forward to trying this one out with my soon to be finished Carton 100/1300 build!

Had an email order confirmation in my inbox this morning showing a projected delivery date of tomorrow.

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scopeboy42
sage

Reged: 03/06/06

Loc: Garner, NC USA

Re: A really F-U-N eyepiece! My new 28mm RKE! new

[Re: Ain Soph Aur]
#5097614 - 02/29/12 01:13 PM

Can those of you who just received or will receive a brand new EO 28 RKE please let me know if you have trouble with the filter threads. I have a new one bought at Christmas and my Japan made filter will only screw in about a 3/4 turn. The filter works fine with my other eyepieces.

Edited by scopeboy42 (02/29/12 01:15 PM)

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Andy Taylor
Twisted, but in a Good Way

Reged: 09/24/08

Loc: The Pub. UK

Re: A really F-U-N eyepiece! My new 28mm RKE! new

[Re: Ain Soph Aur]
#5097687 - 02/29/12 01:49 PM

Quote:

Quote:

The web site shows them to be in stock, so I ordered one this evening. Looking forward to trying this one out with my soon to be finished Carton 100/1300 build!

I use one in my 100mm F13 Carton (self build) and it's wonderful. You'll love it!

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Robert70
sage

Reged: 02/11/11

Loc: The Garden State: NJ

Re: A really F-U-N eyepiece! My new 28mm RKE! new

[Re: Andy Taylor]
#5098277 - 02/29/12 08:00 PM

I have a space for a 28mm. Maybe a dumb question but, the 28mm is sold as mounted and unmounted? They are the same price. I read what they mean by unmounted but I do not quite understand it.

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amicus sidera
Carpal Tunnel

Reged: 10/14/11

Loc: East of the Sun, West of the M...

Re: A really F-U-N eyepiece! My new 28mm RKE! new

[Re: Robert70]
#5098291 - 02/29/12 08:07 PM

I believe that "unmounted" means that only the lenses, and spacers if needed, are supplied... the mounting, whether in an eyepiece barrel or built into a custom piece of optical equipment, is left up to the buyer.

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