Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

Edmund RKE's ROCK!

This topic has been archived. This means that you cannot reply to this topic.
156 replies to this topic

#26 Daniel Mounsey

Daniel Mounsey

    Vendor (Woodland Hills)

  • *****
  • Vendors
  • topic starter
  • Posts: 8,099
  • Joined: 12 Jun 2002

Posted 12 April 2010 - 12:33 PM

So in the 28MM range which one is recommended the RKE or the Plossl?


If you are comparing the 28mm to some other plossl, IMO the RKE hands down. It's such a unique eyepiece. Once you know how to position your eye, it's almost like a peace of space is resting right in front of you without a rim. The 28mm RKS is without a doubt! in my top 10 list of favorite eyepieces of all time.

The 28mm model I was using was the original model along with newer RKE's with the plossl name on it. We didn't have a 28mm RKE that had the plossl name on it.

#27 Clive Gibbons

Clive Gibbons

    Mostly Harmless

  • *****
  • Posts: 16,724
  • Joined: 26 May 2005

Posted 12 April 2010 - 12:34 PM

Hi Daniel.

Are they now different from what's pictured here?

Those look like what I recall using.

Has Edmund modified the RKE barrel to improve effective eye relief in the shorter f.l.'s?

#28 BillP

BillP

    ISS

  • *****
  • Vendors
  • Posts: 21,589
  • Joined: 26 Nov 2006

Posted 12 April 2010 - 12:46 PM

If you look at the 2nd link that EdZ supplied, you can see that the Edmunds Plossl look almost identical, however the top of the EP's volcano is flatened instead of being a deep well like on the RKEs. This alone makes them feel very nice.

Also, the 28 Plossl is not like the 28 RKE. So the Plossl does not give you that floating in space appearance. It just has a very nicely defined field stop and excellent eye relief. I've found that I prefer its view to either my 32mm or 21mm TV Smooth sided Plossls. I've actually stopped using my 24 Pan that much now as the 28 Plossl is a great view!

#29 Daniel Mounsey

Daniel Mounsey

    Vendor (Woodland Hills)

  • *****
  • Vendors
  • topic starter
  • Posts: 8,099
  • Joined: 12 Jun 2002

Posted 12 April 2010 - 12:46 PM

Hi Daniel :)

It sounds like you thought that those Edmund Plossls you tested, were RKEs. So I guess that the takeaway is that the Edmund Plossls are pretty good too and are comparable to the old RKEs.


If that's the case, then yes. I wasn't really paying much attention to the design, but more so just focusing on what I was seeing with both the early and older models of the RKE's. To me, they all appeared to be equally amazing.

#30 Daniel Mounsey

Daniel Mounsey

    Vendor (Woodland Hills)

  • *****
  • Vendors
  • topic starter
  • Posts: 8,099
  • Joined: 12 Jun 2002

Posted 12 April 2010 - 12:51 PM

Clive,

I think Bill is correct. They looked practically identical but I also have to say that if it is the 28mm you are also looking at, I really love the old design. I haven't personally tested the newer 28mm, so I'd go on Bill's comments. What I can say though, is that the galaxies in the mid focal lengths all looked equally good. I do however, find it ironic that the RKE plossl is on $39.95 and the reversed Kellner models at $59.95 go figure.

#31 Dave Mitsky

Dave Mitsky

    ISS

  • *****
  • Moderators
  • Posts: 101,953
  • Joined: 08 Apr 2002

Posted 12 April 2010 - 01:58 PM

I have an old 28mm RKE and have also used 15 and 28mm RKEs belonging to ASH. The 28mm provides a fairly healthy magnification but a tiny true field of view when used with the club's 17" f/15 classical Cassegrain.

There really is something special about the views that the 28mm provides.

Dave Mitsky

#32 Ed Kessler

Ed Kessler

    Apollo

  • *****
  • Posts: 1,242
  • Joined: 17 May 2006

Posted 12 April 2010 - 02:06 PM

Daniel,

Did you ever notice any extra CA when using the RKEs? I had a set for a while and sold them because I noticed that they introduced CA into an otherwise color-free system.

#33 Daniel Mounsey

Daniel Mounsey

    Vendor (Woodland Hills)

  • *****
  • Vendors
  • topic starter
  • Posts: 8,099
  • Joined: 12 Jun 2002

Posted 12 April 2010 - 02:42 PM

Daniel,

Did you ever notice any extra CA when using the RKEs? I had a set for a while and sold them because I noticed that they introduced CA into an otherwise color-free system.


Hi Ed,

It's interesting you mentioned this because many years back I saw the same thing with a particular set of orthos, however with the RKE's that was never the case. Sorry to hear that.

#34 gnowellsct

gnowellsct

    James Webb Space Telescope

  • *****
  • Posts: 19,753
  • Joined: 24 Jun 2009

Posted 12 April 2010 - 03:06 PM

I wish the RKE series had a 10mm. The jump from 12 to 8 misses the sweet spot for me.

I must say, however, that I did repeated tests over one year of the RKE 8 and 12 vs the SPL 10 and the XW10. I really never saw what was the point of the super mono: it had no added value compared to the alternatives. The XW10 matched or exceeded the RKEs in sharpness on all objects including dsos. Anyhow the RKEs are part of my son's observing kit, if memory serves.

regards
Greg N

#35 gnowellsct

gnowellsct

    James Webb Space Telescope

  • *****
  • Posts: 19,753
  • Joined: 24 Jun 2009

Posted 12 April 2010 - 03:10 PM

Daniel,

I am an Edmund RKE newby, but I checked out the edmunds site and they state these are microscope EP's, can they be used on telescopes? Are they 1.25" barrels?

I see they have 32MM RKE which I believe is a 2" barrel, has any tried that one?


The 32mm RKE: I owned that. It's not the same design at all, it's an Erfle.

It's actually rather awful. Don't go there is the bottom line.

I had a 32mm fest one night that included the 32 RKE, 32mm UO Konig, and the 32mm Meade SWA. The 32 RKE was clearly inferior to the other two, tremendous astigmatism on both sides of the eyepiece. This is a very old design, I'm told. Like for WWII tanks or something.

Anyhow I sold the RKE, sold the UO, and kept the Meade until the great XW conversion.

Greg N

#36 starpal

starpal

    Viking 1

  • *****
  • Posts: 521
  • Joined: 05 Aug 2004

Posted 12 April 2010 - 03:19 PM

...I do however, find it ironic that the RKE plossl is on $39.95 and the reversed Kellner models at $59.95 go figure.


Hi Daniel! Great thread thanks for starting it. What I suspect may be the case is their Plossl is now outsourced to China and hence cheaper. The earlier Edmund 28mm 3-element reversed Kellner likely as still USA made at the NJ plant.

Know what? The original 28mm from Edmund was actually a (Symmetrical) Plossl! At one time historically I had a few and LOVED them! Wish I had my archived images handy to show on this thread (anyone got a pic?).

Know what you mean on nice WOW for an image through the 3-element version. There being a little effort to hold the view but worth it! That one, BTW, was why Edmund offered an accordian-styled eyeguard :-) My first ever 80mm finder was designed around this same enhanced performance eyepiece! Was an 11x80 w/ 4* field!

#37 Sol Robbins

Sol Robbins

    Vanguard

  • *****
  • Posts: 2,283
  • Joined: 01 Dec 2003

Posted 12 April 2010 - 03:28 PM

I couldn't find the Plossls on the EO web site.

Only RKE's.

Can you guys assist?

A couple of these might work well in my f/7.46 and f/11 refractors.

TIA,

#38 BillP

BillP

    ISS

  • *****
  • Vendors
  • Posts: 21,589
  • Joined: 26 Nov 2006

Posted 12 April 2010 - 03:32 PM

Edmund Plossl Website

#39 Daniel Mounsey

Daniel Mounsey

    Vendor (Woodland Hills)

  • *****
  • Vendors
  • topic starter
  • Posts: 8,099
  • Joined: 12 Jun 2002

Posted 12 April 2010 - 03:53 PM

Know what? The original 28mm from Edmund was actually a (Symmetrical) Plossl! At one time historically I had a few and LOVED them! Wish I had my archived images handy to show on this thread (anyone got a pic?).

Know what you mean on nice WOW for an image through the 3-element version. There being a little effort to hold the view but worth it! That one, BTW, was why Edmund offered an accordian-styled eyeguard :-) My first ever 80mm finder was designed around this same enhanced performance eyepiece! Was an 11x80 w/ 4* field!


I just always assumed otherwise but never bothered to check, but that's great. I just enjoy the views and leave all the design perimeters to the other guys thanks :lol:

#40 Daniel Mounsey

Daniel Mounsey

    Vendor (Woodland Hills)

  • *****
  • Vendors
  • topic starter
  • Posts: 8,099
  • Joined: 12 Jun 2002

Posted 12 April 2010 - 04:05 PM

Here's a pretty cool 3D model of the standard RKE element design.

#41 CollinofAlabama

CollinofAlabama

    Gemini

  • *****
  • Posts: 3,109
  • Joined: 24 Nov 2003

Posted 12 April 2010 - 05:56 PM

snart, et alia,

I think you're getting things wrong for a lot of people. Don't get me wrong, people using SCTs and apo's on their driven, often go-to mounts, the smaller-is-better philosophy may work for you. But at this past Saturday night's star party 40 miles east of town, everyone had an undriven dob except a friend of mine with his ES 6" achromat-on-Universal Astronomics alt-az and me, with my AstroTech 80ED on the PortaMount.

I just picked up two TV Plossls, but after a brief view through my new 20mm, it got put back in the case, eclipsed by the Pan 19. The Meade 5000 14mm UWA did a WONDERFUL job on M101, arms flying in glory, in another Club member's 20" dob. Nobody even thought of using a pathetic plossl (or less) AFOV eyepiece. I'm certain my 25mm Antares Elite Plossl would have done a great job, but the image would have been much smaller, with about the same level of pushing and moving.

For me, the human factor of driven vs undriven scopes cannot possibly be removed. That said, I'm positive that what we lost in minor detail to a super-optimized, low lens count, poor AFOV eyepiece in an apo of 1/3rd less aperture was more than overcome by the several bazillion more photons the 20" mirror and Meade 5000 14mm UWA put in the eyeball. One must take the situation as it comes, and for the undriven scope world, which often comes with many, many more photons from the light bucket, the wide field eyepiece is the perfect compliment.

We had three 10" dobs, one 8" dob, the 20" dob and the two undriven refractors. Wide field ruled for the folks lucky enough to have them. Those who only had plossls didn't prefer them to those with Naglers and Meade UWAs. At the end of the evening, when I put my Nagler 9 t6 in a friend's new 10" XT, he was only in awe of M13, as was I. The thought of replacing it with his Sirius Plossl 10mm didn't occur to either of us.

I understand if you have hours and hours to pursue this hobby, the driven scope is the best choice, but all of us are amateurs, able to tear ourselves away from the work-a-day world on the occasional grace of being able to get away and fair weather provide. Hey, I'm a married man, thank God! Gotta go pick up the kid,

Ciao,

CDS

#42 MorningStar1969

MorningStar1969

    Viking 1

  • *****
  • Posts: 501
  • Joined: 17 Dec 2009

Posted 12 April 2010 - 05:57 PM

I so wish Edmund was still in the telescope game. Such great memories.

#43 Sol Robbins

Sol Robbins

    Vanguard

  • *****
  • Posts: 2,283
  • Joined: 01 Dec 2003

Posted 12 April 2010 - 06:58 PM

Many thanks Bill!

#44 5u4

5u4

    Mariner 2

  • *****
  • Posts: 214
  • Joined: 27 Apr 2006

Posted 12 April 2010 - 07:32 PM

When looking at the Edmund Plossl's, they all say "Plossl lens" except for the 8mm which says "wide field lens". Wonder what that means?

#45 Mike Hosea

Mike Hosea

    Fly Me to the Moon

  • *****
  • Posts: 6,175
  • Joined: 24 Sep 2003

Posted 12 April 2010 - 07:38 PM

Well, right or wrong, at least it's a lot cheaper than a Brandon thread. ;)

#46 Sarkikos

Sarkikos

    ISS

  • *****
  • Posts: 33,800
  • Joined: 18 Dec 2007

Posted 12 April 2010 - 07:50 PM

OK, how well do you guys predict - or know from experience - that these RKEs will perform in a 10" f4.7 Newt Dob? When I get to a dark site, I usually end up looking through my Baader Hyperion Zoom 90% of the time when I hunt for and observe faint fuzzies. Since I don't have push-to, go-to, or tracking, the Zoom helps me find the galaxy or EN, RN, PN, etc. and dial in the best magnification for that object without having to change eyepieces (and potentially losing the object). I found over 30 new (to me) galaxies last Saturday doing this. The RKE would not have that capability, but maybe it would be worth it for a better view?

I also have a couple no-name wide-view Kellners in my box that I keep bringing to the field but forget to use. One says "KE-25 Wide Angle," the other "KE-10 Wide Angle." The 25mm has about a 55 degree AFOV, the 10mm about 52 degrees. (They came with a used ST80 I bought a year ago.) Should I make an effort to try them out in my 10" when observing galaxies?

Mike

#47 BillP

BillP

    ISS

  • *****
  • Vendors
  • Posts: 21,589
  • Joined: 26 Nov 2006

Posted 12 April 2010 - 08:09 PM

When looking at the Edmund Plossl's, they all say "Plossl lens" except for the 8mm which says "wide field lens". Wonder what that means?


I asked Edmunds that already. They responded that they didn;t want people confusing the 8mm Plossl with the 8mm RKE that they once carried. I know it doesn't make too much sense...maybe it is their top seller? DOn't know. Anyway, the tech confirmed that the 8mm Wide Field is a 4 element Plossl design with a 50 deg AFOV.

#48 gnowellsct

gnowellsct

    James Webb Space Telescope

  • *****
  • Posts: 19,753
  • Joined: 24 Jun 2009

Posted 12 April 2010 - 09:41 PM

Here's a pretty cool 3D model of the standard RKE element design.


Interestingly according to their chart below the schematics, the orthos "win" over the RKEs on most of the critical criteria.

Greg N

#49 Vondragonnoggin

Vondragonnoggin

    Cosmos

  • *****
  • Posts: 8,619
  • Joined: 21 Feb 2010

Posted 12 April 2010 - 09:47 PM

I already ran a thread on my 28mm RKE, but I'll say it again - This is one cool design for an eyepiece and works great barlowed too. The view spills over the edge of the barrel. Looks like space is sort of floating above the eyepiece. Out of any eyepiece I own, this would be one of the hardest to part with and I would definitely buy another if I lost it or it was damaged. Great price. Mine is a bit older and I got it used with my astroscan, but was worth the price of the astroscan alone. I haven't tried any others yet, but the 28 is a keeper.

#50 coopman

coopman

    Fly Me to the Moon

  • *****
  • Posts: 7,113
  • Joined: 23 Apr 2006

Posted 12 April 2010 - 10:04 PM

So, for those of us that are impressed by Daniel's lead-off post, the Edmund 28mm PLOSSL is the one to order?


CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics