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Criterion ASP eyepieces - quality ??

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#1 AaronM

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Posted 19 February 2013 - 12:21 AM

Hello friends,

i have the chance to get 3 vintage Criterion eyepieces, that I would like to use with my old ornage C8. They labeled as ASP 30 mm, ASP 18 mm and ASP 12,7 mm in 1,25" barrels. I could get them for 20 € !

I don't know anything about Criterion eyepieces, but I guess that they have the Kellner design ?

Whats about the quality ? Should I buy them for my C8, or are they garbage ??

Kind regards, Michael

#2 Littlegreenman

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Posted 19 February 2013 - 04:16 AM

Hi Michael,

Here is a link to a short discussion on this line a few years back:link

A few comments: these are not Kellner's; they are "achromatic symmetrical Plossls." The term Plossl as it has been applied to eyepiece design has not been as standard as you may think. A "symmetrical" Plossl is two groups of doublets that are mirrored in order. Some over the years have marketed or highlighted eyepieces with that design as being a "true (real) Plossl."

So, on the one hand they were trying for the cachet of the "true Plossl" design, while hiding the fact behind the acronym, A.S.P.!

In the link above the general consensus is that they are good or better eyepieces, while also being economical.

I have an 18mm one, branded Bausch & Lomb. It's a nice eyepiece, good contrast, no major problems, and comfortable to look through.

LGM

#3 Ducky62

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Posted 19 February 2013 - 11:28 AM

I have 3 B&L Criterion ASP EPs. If I'm remembering right the 12.7mm was pretty good. If it is 20 for all three (and not each) I can't see how you can go wrong.

#4 Joe Cepleur

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Posted 19 February 2013 - 11:37 AM

With an orange tube C8, the issue is not just how good the view is, given that modern eyepieces will likely be better. There is also the historic value of seeing the view as it would have been seen back when the scope was new. From that point of view, coupled with the consensus that these are good eyepieces anyway--and especially at 20 Euros for the set!--these are must-buys.

#5 GeneT

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Posted 19 February 2013 - 04:26 PM

Mine were just average. They might make a great collector's item. In my opinion, the newer designs are better all around.

#6 AaronM

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Posted 21 February 2013 - 12:30 AM

Hello friends,

I did it ! The price was now 22 € including shipping ! I suppose, I can't go wrong for this price and my loved old ornge C8 is very eye-piece-friendly !
I will report my first impressions if I have first-light with them ( but here in germany in my town it is raining and cloudy since 4 weeks :smirk: :p).

Regards, your's "Kraut" Michael

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#7 BigC

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Posted 21 February 2013 - 01:22 AM

3 A.S.P. for 22 euros is a good deal I think;have he B&L 18 and 30mm here and they seem fine for my scopes.Remember older scopes tended to longer,more forgiving focal lengths.

#8 Mirzam

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Posted 21 February 2013 - 07:13 AM

The main issue with the ASP's is that the apparent field of view is quite narrow. They are also easy to disasemble and clean, which can mean that elements may get flipped around in the process. I've had several of these eyepieces that had to be restored to place the optical elements back in the proper orientation. If they give nice sharp images on axis then all is well.

By the way, none of mine have had mirror image optical elements so I'm not sure about the name.

JimC

#9 Karl Fabian

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Posted 21 February 2013 - 11:19 PM

I have the complete set of ASPs (30, 18, 12,7, 9, 7) Most of my set are Bausch & Lomb labled with one Criterion. They are all identical nice quality manufacture made in Japan Circle Y. They are good eyepieces comparable to typical moderate priced Plossls but as mentioned previously the fields are not large... particularly the 30mm which is about 35 deg. The best of the set is the 18mm with about 48 deg field. The main problem is the filter threads are non-standard. They deliver good performance down to about F6.

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#10 Littlegreenman

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Posted 22 February 2013 - 03:33 AM

(snip)

By the way, none of mine have had mirror image optical elements so I'm not sure about the name.

JimC


And I thought I was spreading Truth! :foreheadslap:

Oh well.
SL

#11 Jean Mario

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Posted 05 April 2013 - 08:34 AM

I have a lot, branded Bausch & Lomb. It's a nice eyepiece, good contrast, no major problems, and comfortable to look through.

#12 Steven C

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Posted 10 September 2013 - 12:52 PM

I have the 12.7mm A.S.P. Spectrum Dispersion eyepiece ... very unique in that you can view the spectra of stars and see the emission and absorption lines. Very cool looking at open clusters ... you can immediately see which "don't belong"

#13 mattyfatz

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Posted 10 September 2013 - 10:34 PM

I'm looking for mine right now. I have 2, 30mm. One is 1/2 inch taller than the other! I never understood why. When I find them I'll post a pic.

#14 Chuck Hards

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Posted 11 September 2013 - 08:37 AM

I have made many true symmetrical eyepieces over the years, and found them to be exceptional in f-ratios slower than f/8, pretty darn good at f/6 & f/7. Not the widest field in the world, but the definition on-axis is tack-sharp, and not bad a bit further out.
The trick is to not use component achromats that are too fast by themselves. Surplus achromats faster than about f/2 rarely give good definition in a true symmetrical. The field can start curving wickedly.

If a manufacturer actually sold a true symmetrical, chances are that it's decent.

#15 highfnum

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Posted 12 September 2013 - 06:23 AM

I have a few
there ok - nothing bad
field of view kinda old fashion






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