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Orion's Explorer II (Kellner eyepieces)

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#1 Blair

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Posted 30 October 2005 - 06:42 PM

I've not posted here before mainly because the Naglers, the Taks, and other expensive eyepieces dominate the discussion.

But I have found that, in my 102m f/5 achromat, the 25, 20, 17 and 13mm Kellners actually show more stars than many Plossls including Televue's.

I admit at higher powers, in my C80ED, a Vixen LV is a better eyepiece than the Kellners with a barlow. (The Kellners show a halo on Mars where the Vixens do not).

Also, this probably applies only to small scopes like I own.

Just food for thought. :grin:

#2 jwaldo

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Posted 30 October 2005 - 10:08 PM

I have the 17 and love it. But one minor correction: At least the 17mm is actually a plossl. Not sure about the others. I had to take mine apart to clean some crud out...

#3 erik

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Posted 30 October 2005 - 10:11 PM

interesting. i owned a couple of orion explorer ep's a few years ago. i didn't think they were bad, but i felt that the sirius plossls i replaced them with were a bit better. seeing more stars might be possible with the explorers due to the fewer elements, however, with today's coatings, more elements doesn't usually hurt the views. were you comparing identical size ep's to come to this conclusion?

#4 Blair

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Posted 30 October 2005 - 11:24 PM

Compared 20mm of Sirius, Highlight and Televue Plossls. I did compare a 17mm Televue Plossl I bought on Astromart with the Explorer II 17mm and the 9 to 10 mag stars in M45 were a little easier to see in the Explorer II.

Basically, for strictly low power use in a small rich field scope I've found the cheaper eyepieces are effective enough.

Also, I could not tell a difference between a 40mm Televue Plossl and a Sirius 40mm in my 102mm Mak. I sold the Televue.

Also, I've not been able to tell a difference between a Sirius Plossl and a Highlight Plossl but then I do not use below 17mm because of eye relief.

I use Vixen LV eyepieces below 17mm because of their 20mm of eye-relief and their very good performance at 100X power and higher.

Again, much of this is probably only true for small scopes with wide field of views. As the focal length approaches 2000mm or higher I wouldn't think a 20mm Explorer II at 100X would perform very well on Jupiter.

#5 jwaldo

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Posted 31 October 2005 - 01:28 AM

I'll have to check my 6mm Explorer II. The Orion ad says they are "3 and 4 element eyepieces" so I assume some are Kellners and some are Plossls....

#6 hoof

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Posted 31 October 2005 - 02:11 AM

I can vouch for the 17mm being a plossl. I had an Orion Sirius Plossl 17mm and they were exactly parfocal, and the lenses reflected light in the same way except for coatings (the Explorer II's had inferior coatings, as you might expect). The 10mm appears to be a true Kellner, and the 6mm might have been too.

The 10mm is surprisingly good, IMO. I've had people do blind tests with it vs a 10mm Plossl, and usually the Explorer II comes out as slightly better.

#7 Scott Beith

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Posted 31 October 2005 - 10:35 AM

The 6mm and the 17mm are Plossl's, the rest are Kelners. I have the 6mm and it is a nice little EP. Very sharp and clear. I use it all the time.

#8 Tom T

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Posted 31 October 2005 - 11:16 AM

Hi blair,

I've noted the same thing. A buddy of mine has the whole set, and the performance is amazingly good - especially in terms of overall throughput.

I've thought about picking up some myself (the kellners) but just haven't pulled the trigger - yet.

Tom T.

#9 Blair

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Posted 31 October 2005 - 08:00 PM

Hello Tom,

Which scope are you going to use them with?

I really liked the 6mm when I owned Orion's 90/910mm refractor but in the last few months eye relief has become more important. So, I have Vixen's 6mm LV.

#10 erik

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Posted 31 October 2005 - 09:23 PM

i'm a bit confused. if the 17mm explorer is a plossl, and has inferior coatings, how does it perform better than the sirius plossl with its better coatings? :question: ...in addition to the 1.25" versions i had, i remember having some .965" explorer's years ago that had some internal reflections. not sure if they were the explorer II's though...

#11 hoof

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Posted 01 November 2005 - 01:21 PM

Erik, if you're referring to my comment about the Explorer II coming out ahead, I was referring to the 10mm Explorer II which is not a Plossl.

Optically I could tell no difference between my 17mm Sirius Plossl and my 17mm Explorer II. One had a green eye lens coating, the other had a blue coating. One had an eyecup, the other didn't.

#12 Tom T

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Posted 01 November 2005 - 02:28 PM

Hello Tom,

Which scope are you going to use them with?

I really liked the 6mm when I owned Orion's 90/910mm refractor but in the last few months eye relief has become more important. So, I have Vixen's 6mm LV.


Hi Blair,

If I do pick them up, it will probably be for use in one of my refractors @ f5.9, f7, f7.9, f8 or f8.6.

T

#13 erik

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Posted 01 November 2005 - 09:52 PM

Erik, if you're referring to my comment about the Explorer II coming out ahead, I was referring to the 10mm Explorer II which is not a Plossl.

Optically I could tell no difference between my 17mm Sirius Plossl and my 17mm Explorer II. One had a green eye lens coating, the other had a blue coating. One had an eyecup, the other didn't.

oh, that makes sense. i must've misunderstood your post... :)


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