Edmund Optics RKE Eyepieces

[johnt]

I recently got interested in ordering some Edmund Optics RKE eyepieces. As a purists minimal element eyepiece, they seem to get very good reviews, and are supposed to have "excellent" light transmission. One such review (for planets) is:

http://www.cloudynights.com/documents/planetaryeyepieces.pdf

So, I proceeded to the Edmund Optics website to look into them, including the price. When I was first checking out the prices of the Edmund RKEs, they came up as $85 each, but when I changed the country to Australia (top right hand side of Edmund Optics website), the price jumped to $137.70 each! I was quite puzzled about why the price should be so much higher for Australia. Then, after I was contacted by Edmund Optics Singapore who are the sales support for Asia-Pacific, including Australia, they informed me that the higher prices are in "Singapore Dollars", not Australian Dollars. So, the $137.70 is really only AU$108. And there is a possibility that they could provide a quote with an even cheaper price that may bring them down below $100 each! Now that looked much better to me!:)

So, I decided to order all of the 1.25" RKE eyepieces (8mm, 12mm,15mm, 21mm, 28mm) but decided against the 2" 32mm RKE Wide-Angle, which was well over $300. I also added a few rubber eyeguards, 2" and 1.25", as I believe they are not easy to get elsewhere.

The price to Australia, being in "Singapore Dollars" is not at all made clear on the Edmund Optics website. So, I hope that this information helps others when deciding if they should order these eyepieces.

Edumd RKE 1.25":
http://www.edmundoptics.com/microscopy/eyepieces/edmund-optics-rke-precision-eyepieces/2075

Edumd RKE 2" 32mm Wide Angle:
http://www.edmundoptics.com/microscopy/eyepieces/edmund-32mm-rke-wide-angle-erfle-eyepiece/2074

Rubber eyeguards:
http://www.edmundoptics.com/microscopy/eyepieces/rubber-eyeguards/2064

[MattT]

I use a pair of RKE 28's in WO bino's and they are something special nearly legendary, if one can handle the ER. The eyepieces melt away...so it seems to me. Would like to hear what you think of the other FL's in the RKE's John, specially compared to the 28's. Edmund Optics in Singapore are great to deal with.
Matt

[dannat]

john its prob too late now but matthew from telescopesandastronomy had a couple of rke's for 70

[johnt]

Matt, buying X2 of some of the Edmund RKEs crossed my mind, but I did not know which ones. So, I thought I would go for one of each first, and then place another order. It does get expensive with the X2. I have already got a full set of University Optics Orthoscopics (old style), and although no bino-viewer yet, I tried to double up on most of them for that same reason in anticipation. Then I want to also look at some other interesting eyepieces from Siebert Optics, and perhaps double up on some of those also. Can I ask which Bino-viewer you have, and if you are happy with it? (Sorry, worked it out - William Optics). John.

[johnt]

Thanks Daniel,
Yes, too late as far as my order goes, but I may want to double up on a few later. But, looking on the telescopesandastronomy webpage, I can't seem to find them yet, so maybe they are sold anyway.

(Found them..Looking again, yes, the 8mm & 21mm RKEs are still listed at $70. )

John.

[FlashDrive]

Have to agree with Matthew...these are legendary Eyepieces ( RKE 28mm) ..and yes....position your eyes in the right place and .....WOW...what a view ...for me ...you feel like you could ' fall ' through them.

I also use them in Bino's.... Awesome Space Walking Wide Field views...

You won't be dissapointed IMHO....I have 3 of these beauties.

Flash........:D

[gb_astro]

Col, that third eye must come in handy. :)

gb.

[FlashDrive]

:D .... Well ...I did ask for that ...didn't I ......:rolleyes:

[johnt]

Thanks Col.

Now I wish I ordered two, at least for the 28mm, and maybe the 21mm.

I assume by the comments about positioning the eye, it's due to the long eye relief, and they would benefit from long rubber eyeguards to help position the eye?

[MattT]

Hi John,
Nows the chance to make Flash an offer he can't refuse....The 28's in a binoviewer, which is basically a two eyed barlow, do have a bit long ER and the rubber eye guards will get in the way of the view big time. I use a towel over my head, nice when it's cold and it's a bit like staring at the shapes that turn into a 3D picture...everything else melts away and your left with what your looking at....:eyepop: The 28's become the ideal 14mm eyepiece (mono view) which in my scope is the best FL for DSO's.
Flash how are the Denks compared to the WO bino's?
Matt

[FlashDrive]

Matt.......In the Denk's ....very nice indeed...like a ' glass port hole ' ....yes...keep your eye's steady ( it's not hard )...and enjoy the ' expansive view ' ...there's nothing quite like it.

As for WO Bino's....I have owned those in previous day's...very nice also and very reasonably priced.....but haven't used the 28's in them .....simply because I didn't have a ' pair ' of them at the time.

No doubt ...the 28's would still be worth it for a WO Bino.

Flash.......

[johnt]

I have managed to get another 28mm RKE added to my Edmund order -thank you for your influence Matt & Col. On the WO bino's, the only limitation would be the smaller prism (20mm) vs the larger (25-27mm) prism of the more expensive ones, which affects the light transmission, and may limit the dimmest objects. The following review seems to put it quite well: http://www.scopereviews.com/page3j.html (http://www.scopereviews.com/page3j.html)

I have not yet decided on which way to go. Start with the $200-300 version perhaps, or go right to the expensive ones?

[bytor666]

The 32mm, 2" Edmund Erfle has little to be desired in a fast scope. It'd prob be great in a longer FL scope tho.

Cheers,

[johnt]

The WO Binoviewer packages with the two WO 20mm eyepieces (NEW) are listed on ebay right now for $199+$19post. I thought I would try those first and bought one, but there are another 9 left if anyone else wants one:

http://www.ebay.com.au/itm/161014939257?ssPageName=STRK:MEWNX: IT&_trksid=p3984.m1439.l2649

[FlashDrive]

@johnt.....that's the way to go...!!

Flash......

[brian nordstrom]

:D Good choice John , I use the supplied 20mm's and a cheep pair of Bintel 40mm plossls that work great in my WO binoviewers , its hard to go back to cyclops viewing once you have experienced using binoviewers .
The RKE's sound like the go , but be happy with what WO's come with , these work well even with the supplied barlow .
I dont need that when using my Tak M210 it reaches focus without it , and the moon is scaryly good using 2 eyes in this scope .
Brian.

[brian nordstrom]

:thumbsup: Oh yes my Zeiss also binoviewer's very well without the barlow .
Brian.

[johnt]

Thanks for the information Brian.

From anyones experience, is there a practical limit for these WO binoviewers in terms of the lowest focal length eyepiece, or maximum power? On say a 1000mm long scope, would you go down as low as say 15mm eyepiece (x67), or even a 10mm eyepiece (x100)? Or is it simply, occasionally enjoying the bino view for the wider field lower magnifications, only with the longer FL eyepieces? I guess I'm asking partly so I know how much money I have to spend in doubling up the lower focal length eyepieces.

John

[brian nordstrom]

:) John , I am out tonight using my Istar 127mm f/8 achro 1000mm f/l and with the 40mm eyepieces its about 60x thru the BV's not the 25x a 40mm would normally give , I think they act as a kind of barlow , like Matt said earlier on here in this thread , and the moon is so awsome in this combo tonight 60x with the 40mm's and 120x with the supplied WO's , you really have to see it to beileve how good using 2 eyes thru a refractor is .
You wont be dissapionted .
Brian.

[brian nordstrom]

:D For all who are interested , a photo taken 15 minitues ago just before I had to move the scope .
The views were so good I never even noticed the rubber eyeguard falling off one of the Bintel plossls until just now .... all fixed .
Brian.

[MattT]

I use down to a 12mm eyepiece with no problems at all. I do have a pair of Agena SWA 10mm eyepieces but the ER is a bit tight. I think your limited by how dim the image gets, the more aperture the better here, and have read that below 10mm FL it gets harder to merge the images but have no practical experience there. The other way is to use a 2X OCS, or a barlow, instead of the 1.6 OCS or put the 1.6 on the front of the diagonal. A few options, lots of options. I'd try the RKE 15 and 12 mono and decide if you like em enough to go double. Try them in the bino's as a single eyepiece, thats what I did. I prefer changing eyepieces than taking out the bino's to change OCS's.
As for wide field of view every eyepiece above with a field stop greater than whatever the bino's field stop is, will vignette due to the field stop in the bino's. Still can get all of Omega Centauri in the bino's with 15mm 70 degree eyepieces for instance with the 1.6 OCS.
Good choice to start with the WO's :thumbsup:
Matt

[denis0007dl]

I really enjoy use my 28mm RKEs in my Mark V bino on 10" f/5 dob. I also had RKE 8mm, and it was not so good, better combination is 28mm RKE + barlows or even better Powermates!