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Edmund RKE 12mm and 8mm vs ORTHOs

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#1 denis0007dl

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Posted 05 February 2013 - 03:58 PM

I would appreaciate if someone can share experience how performs Edmund RKE 12mm and 8mm vs ORTHOs 12,5mm and 8mm (UO, BGO or simillar) on planets in terms of contrast, sharpness,....

Thanxs!!!

#2 saemark30

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Posted 05 February 2013 - 05:27 PM

RKE don't work in fast dobs unless barlowed.
The orthos are sharper, and have full multcoatings hence better contrast.
Televue plossls are great as well.

#3 iluxo

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Posted 05 February 2013 - 07:02 PM

Having had a set of RKE's in the 1980's and 90's, as well as a 9mm and 12 mm ortho... I used the RKE's and not the orthos. I also sold all of these eyepieces years ago and replaced them with a set of Vixen LV's (far better) and now LVW's.

Both of these are now very old designs - they are nothing to aspire to.
It's not hard to find better budget eyepieces than the RKE - many cheap chinese widefield clones will be better. As for orthos, having had a 9mm and 12mm ortho many years ago I would not buy them either with the possible exception of Zeiss ones.

if you want some good high-power eyepieces on a budget and can live with the field of view, the Vixen LV's or NLV's are still a good choice.

My own experience:

a) RKE's have a fair bit of field curvature and pincushion distortion. In a Newtonian, optically the RKE's are tolerable in f/5 scopes but not good below f/4.5

B) The 8mm RKE has very short eye relief, making it somewhat hard to use and uncomfortable. Orthos are no better. The same can be said for 12mm.

c) The RKE's have a small field of view by modern standards which means getting an object into the field and keeping it there will be just a little bit harder than with wider eyepieces.

#4 BillP

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Posted 06 February 2013 - 11:23 AM

A set I had from the late 1990's early 2000's was phenomenal. The 8mm was exactly on-par with the TV 7.4mm Plossl for planets. Picked up some newer vintage ones about a year or 2 ago and they were no where near as good...giving soft images at best for planetary and easily surpassed by other Orthos and Plossls.

The eye relief does "feel" tight on the 8mm, however that is because of how deeply the lens is inset in the housing. If moved up the eye relief would be quite generous feeling for an 8mm. However, the 8m TV Plossl feels very tight as well so no advantage there in the eye relief department IMO. A 7mm volcano Ortho feels best of the three for me.

As a side, with that older set I had, the RKEs were phenomenal on M42 and the Trap. The RKEs would routinely pull in Trap E & F cleaner than any other eyepieces...including my orthos and wide-fields. So they were a wonderful set for that.

Sadly though, IMO the current production RKEs seem to have lost something over the years as not performing as well. Exception is the 28mm RKE which IMO everyone should experience with its "floating" view. I keep that one and use it semi-often in my scopes, including my f.4.7 Dob as it is plain fun! It is also exceedingly good with high power Barlow for planetary (although the ER gets really long...but you gotta take the bad wit the good for all eyepieces)

#5 denis0007dl

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Posted 06 February 2013 - 12:22 PM

A set I had from the late 1990's early 2000's was phenomenal. The 8mm was exactly on-par with the TV 7.4mm Plossl for planets. Picked up some newer vintage ones about a year or 2 ago and they were no where near as good...giving soft images at best for planetary and easily surpassed by other Orthos and Plossls.

The eye relief does "feel" tight on the 8mm, however that is because of how deeply the lens is inset in the housing. If moved up the eye relief would be quite generous feeling for an 8mm. However, the 8m TV Plossl feels very tight as well so no advantage there in the eye relief department IMO. A 7mm volcano Ortho feels best of the three for me.

As a side, with that older set I had, the RKEs were phenomenal on M42 and the Trap. The RKEs would routinely pull in Trap E & F cleaner than any other eyepieces...including my orthos and wide-fields. So they were a wonderful set for that.

Sadly though, IMO the current production RKEs seem to have lost something over the years as not performing as well. Exception is the 28mm RKE which IMO everyone should experience with its "floating" view. I keep that one and use it semi-often in my scopes, including my f.4.7 Dob as it is plain fun! It is also exceedingly good with high power Barlow for planetary (although the ER gets really long...but you gotta take the bad wit the good for all eyepieces)


Interesting, older RKEs that are better than newer ones!
o, using RKE 28mm with powermate does not extend eye releaf, so it would be great for planetary work also?!?!?!

#6 MRNUTTY

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Posted 06 February 2013 - 01:04 PM

Bill, so to be sure. Are you referring to the recent Edmund Scientific Plossl's or the recent Edmund Optical RKE's? I have the EO RKE's and haven't had a chance to give them a definitive 'grade'. But it feels like they're at least better than the recent TMB PII's; whichever ones I have. :D

#7 Sarkikos

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Posted 06 February 2013 - 01:49 PM

Bill,

Sadly though, IMO the current production RKEs seem to have lost something over the years as not performing as well. Exception is the 28mm RKE which IMO everyone should experience with its "floating" view.


My experience with older RKE's is that the QC is sketchy, to put it mildly. The ones that I've seen have uneven field stops, burrs and such along the edge. The new RKE's have clean, sharp field stops, for what that's worth. IME, neither old nor new RKE's are as sharp as a decent ortho, such as the BGO's, or Brandons. Just the luck of the draw? Many other lines are at least consistent. The RKE's are not. You buy a used RKE, you don't know what you're getting. Drawing from my own experience, I'd rather take my chances with the newest version.

I have a new pair of the RKE 28's. They are keepers, for the "floating effect" if nothing else.

Mike

#8 csrlice12

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Posted 06 February 2013 - 01:52 PM

"whichever ones I have."

Next up class; "How to tell when you have too much stuff" :lol:

Don't have any RKEs, but the UO orthos I have put up some pretty good views in my refractor (haven't even put them in the dob, too narrow a FOV). They have excellent contrast and sharpness. That being said, with my other eyepieces in those same f/ls, they don't see a lot of use, but I do use them because they don't affect the scope balance like some of the other eyepieces do (go from a 12mm Ortho to the 7mm Pentax, and it's gonna have some effect on the balance).

#9 Sarkikos

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Posted 06 February 2013 - 01:54 PM

I have the EO RKE's and haven't had a chance to give them a definitive 'grade'. But it feels like they're at least better than the recent TMB PII's; whichever ones I have. :D


I'd say that the newest RKE's are at least better than the recent TMB PII's - or any version of the TMB PII's, for that matter. But then, that's not saying much. I have to admit, though, that the TMB PII's do have a consistently more even field stop than some of the older RKE's. Eh... :shrug:

:grin:
Mike

#10 Sarkikos

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Posted 06 February 2013 - 02:07 PM

Bill,

A set I had from the late 1990's early 2000's was phenomenal. The 8mm was exactly on-par with the TV 7.4mm Plossl for planets. Picked up some newer vintage ones about a year or 2 ago and they were no where near as good...giving soft images at best for planetary and easily surpassed by other Orthos and Plossls.


Maybe the late 1990's and early 2000's were the Golden Age of the RKE's? Could it be that RKE's from before and after the Golden Age are not as good? Perhaps my experience with older RKE's involved some real, old clunkers. I would prefer the newest version anyday over those.

There are wildly differing opinions on the performance of RKE's. Maybe part of the reason is that the QC of the line has varied so much over the years.

Personally, I don't think it's worthwhile playing the RKE Lottery. We should just get a pair of the new RKE 28's and be done with them. At least with used BGO's and new BCO's you know what you're getting ... and that's better than any RKE's I've seen.

:grin:
Mike

#11 BillP

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Posted 06 February 2013 - 02:27 PM

There are wildly differing opinions on the performance of RKE's. Maybe part of the reason is that the QC of the line has varied so much over the years.


Denis/John/Mike,

Very true that there are lots of opinions on the QC of the Edmund RKEs. Frankly I never had much problem with them...the older varieties. Just the newer ones gave me issues when I purchased several new. Actually had to send them back as they were delivered with cracked lenses, then the replacements were bottom of the list when I did a personal shootout of 8mm RKE, TV Plossl, Brandon, AP-SPL, TMB Supermono. In that testing, which I did over almost a whole year, the AP-SPL and TMB were neck-in-neck with the Ap eventually winning. The Brandon placed next, then the TV Plossl, then a very distant last was the RKE. This was only for lunar and planetary performance.

btw, yes, all my comments are for the Edmund RKEs and not the Plossls. The Edmund Plossls are great...with their only weakness being IMO that they are apparently single coated so not as bright as multicoated fare.

#12 csrlice12

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Posted 06 February 2013 - 02:43 PM

Could it be that they're being mfg in China now. Ever see pics of the air in Beijing???? Doubtfull if these mfgs are using "clean rooms" to mfg eyepieces, let alone what's finding its way into the glass making process itself......

#13 MRNUTTY

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Posted 06 February 2013 - 03:02 PM

"whichever ones I have."

Next up class; "How to tell when you have too much stuff" :lol:


Just to clarify my comment :-) There is so much confusion about the TMB PII's lately that when I bought a pair off UK EBay, and emailed him after concerning whether the auction photo was a file photo or a pic of the ones I bought. He sent me back a rather extended email describing the "debates on CN", and the lengths they went to to try identify the lineage of the EP'; contacting what's left of Burgess Optics and TMB, and little interest the company had in matter. And regardless of the known or suspected authenticity of the EP's I bought, he was sure they were fine EP's as their other clients adored them, and I should as well. I appreciate the extent to which he went to stand behind his wares.

So, my comment meant to clarify the confidence I had in the comparison with TMB's. And yeah, I have too much stuff, but I like it :-)

#14 denis0007dl

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Posted 06 February 2013 - 03:20 PM

There are wildly differing opinions on the performance of RKE's. Maybe part of the reason is that the QC of the line has varied so much over the years.


Denis/John/Mike,

Very true that there are lots of opinions on the QC of the Edmund RKEs. Frankly I never had much problem with them...the older varieties. Just the newer ones gave me issues when I purchased several new. Actually had to send them back as they were delivered with cracked lenses, then the replacements were bottom of the list when I did a personal shootout of 8mm RKE, TV Plossl, Brandon, AP-SPL, TMB Supermono. In that testing, which I did over almost a whole year, the AP-SPL and TMB were neck-in-neck with the Ap eventually winning. The Brandon placed next, then the TV Plossl, then a very distant last was the RKE. This was only for lunar and planetary performance.

btw, yes, all my comments are for the Edmund RKEs and not the Plossls. The Edmund Plossls are great...with their only weakness being IMO that they are apparently single coated so not as bright as multicoated fare.


Very interesting! I have luck and borrow Edmund RKE 28mm and 8mm and test them on my 10" f/5 dob vs BGO 9mm....

Posted Image

Sky is not exellent crisp as it should be, but I see warmer image in RKE 8mm, and less sharper image than BGO 9mm, also, BGO produce more contrast!

After testing, I take RKE 8mm, turn it, and se CRACKED LENS on corner...

Posted Image

#15 denis0007dl

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Posted 06 February 2013 - 03:25 PM

I have also tested RKE 28mm vs GSO Plossl 32mm...RKE gives floating effect, very interesting, and seems sharper and contrastier image than Plossl

Posted Image

#16 BillP

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Posted 06 February 2013 - 04:01 PM

Could it be that they're being mfg in China now. Ever see pics of the air in Beijing???? Doubtfull if these mfgs are using "clean rooms" to mfg eyepieces, let alone what's finding its way into the glass making process itself......


Edmund sells these marked as "Made in the USA" and I recently emailed them and they reiterate that the optics and housings are made in the USA.

#17 BillP

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Posted 06 February 2013 - 04:12 PM

Here's what the new one I purchased back in late 2011 looked like...

Attached Files



#18 Sarkikos

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Posted 06 February 2013 - 05:05 PM

Ouch! :tonofbricks:

The only new version RKE's I have purchased are a pair of 28's, and they are excellent in fit and finish and optics - not necessarily up to the performance of other eyepieces, but the QC was AOK. Maybe the larger lenses are easier for EO to get right.

On the other hand, nearly all the used old version RKE's I have bought had some problem with fit and finish, mostly those raggedy field stops. :ohgeeze: No cracked or otherwise damaged lenses, though. But IMO, the performance wasn't up to decent orthos or even TV Plossls.

Mike

#19 ngc2289

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Posted 06 February 2013 - 11:58 PM

But Bill the lenses are supposed to be cracked. Cracking the lenses is done at the factory in order to eliminate all stress in the glass. Getting the stress out improves the images!! :smash: :smash: :smash: :smash: :ubetcha: :ubetcha: :ubetcha: :ubetcha: :ubetcha: :ubetcha: :waytogo: :mrevil: :mrevil: :mrevil: :mrevil: :mrevil:

#20 BillP

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Posted 07 February 2013 - 09:59 AM

Surprisingly...on non-Lunar/Planetary objects that very obvious crack had fairly little impact on the view!!! Turning to planetary the views where then not so sharp...then the replacement without the crack were still rather soft compared to others.

But yes, appears based on the few photos that this may be part of their new design :lol:

#21 MRNUTTY

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Posted 07 February 2013 - 11:55 AM

I checked all my RKE last night. No cracks :-)

#22 bremms

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Posted 07 February 2013 - 01:31 PM

Had the 8mm RKE twice. It's no match for a 9 or 7mm UO ortho. My 7.4mm TV Plossl was better too. Both the RKE and the plossl are gone. The orthos remain. I like the TV plossls at 13mm and up. Orthos below that. 28mm RKE?? Great eyepiece.






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