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University Abbe Orthoscopics

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#76 astro_baby

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Posted 06 October 2011 - 12:39 PM

Well to be honest I never knew Glen was selling them until after I bought the first two - by then I wanted them all to look the same ( I have moderately severe OCD ) . But I also had in mind resale value.

#77 t.r.

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Posted 06 October 2011 - 01:06 PM

by then I wanted them all to look the same ( I have moderately severe OCD ) . But I also had in mind resale value.


:lol: I think we all suffer from it to some degree! :grin:

#78 azure1961p

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Posted 06 October 2011 - 11:12 PM

My standard comment about Orthos involves the completely flat exit pupil (in optical language, no spherical aberration of the exit pupil). You can put your eye anywhere in the exit pupil and the view is the same. For looking at planets, you don't even need the whole 40 degree field, just the central 10 or 20 degrees, so you can use the short ones for high power viewing at some comfortable distance from the eye lens. Even Plossls will not allow this, and widefields demand that the eye be in a specific place in the exit pupil. This adds up to complete eye comfort and no dropout effects from a moving head. Being forced to fix one's head in one place to use a widefield adds up to muscle strain that diminishes one's ability to see fine details. This is particularly important with Newtonians where one may be standing up and the head wavering to and fro (the older I get, the harder it is to stand stock still).

The other consequence is a field stop that appears to be effectively at infinity. This gives deep sky objects an objective and crystalline appearance, and the telescope seems to melt away. This is what I most love about Orthos. The telescope disappears and one is in direct touch with the field of view, like looking out a window.

So Orthos are all about eye comfort and a strong "clinical" view, despite the short eye relief in the shorter focal lengths. The UO Orthos are all winners!

-drl


Excellent post. I agree 100%. And i do enjoy comfortable eye relief even with my 4mm abbe just because i keep that ten or twenty degrees centered on the planet. I love my orthos. I only regret i cant get a 3.5mm UO ABBE.

Pete

#79 great_bear

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Posted 07 October 2011 - 01:22 AM

I wanted them all to look the same


Well that's fair enough really :) - even I express a shudder when a forum poster says: "Here's my set of orthos" and puts up a photo showing a mixture of UO and unbranded Circle-Ts!!

I think to myself - that's not a set, that's an assortment!

#80 deSitter

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Posted 11 October 2011 - 09:33 PM

I'll bet jbarnett, the eyepiece hooligan, has a complete set of 6mm Orthos!

-drl

#81 wprince

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Posted 12 October 2011 - 06:33 AM

Hello all, I know I'm posting very late to this thread. I've always wanted some more University Optics orthos, I only have my one 7mm HD version. However, I just checked the price on the UO website, almost $90 plus shipping for new ones!? THAT is a significant price increase (previously I checked they were about $55). I won't say $90 a piece is too much, but that places pause in acquiring the whole set. Don't the HD's cost just little bit more? I will say the I found the 7mm HD excellent, and more comfortable to use than a 11mm TV plossl I used to own as far as eye relief.

#82 wprince

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Posted 12 October 2011 - 06:36 AM

Ok, not quite $90, but $85.95 each. My apologies.

#83 tomchris

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Posted 12 October 2011 - 07:26 AM

When the longer focal length abbes are barlowed, does anyone find a real noticeable decrease in contrast? :question: I've been thinking of buying a shorter focal length UO Abbe but maybe just barlowing my 12.5mm or 9mm will give me larger eye relief as well as the increased magnification without too much loss of contrast.

#84 Jim Rosenstock

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Posted 12 October 2011 - 07:42 AM

They barlow quite well. Uae good barlow, of course.

Short eye relief doesn't bother me a bit, so I go for the "least glass" option....

...but there's a reason every great set of Orthos comes with a barlow.

Enjoy!

Jim

#85 Monoeil

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Posted 12 October 2011 - 08:43 AM

As Jim stated, as long as you use a quality barlow lens, you should not notice any major negative effect.

Some prefer short focal lenses, other (like me) favor the use of barlow lens for a better comfort there is no universal answer. It is really a matter of personal taste. :)

From the financial standpoint, the barlow lens solution is somewhat economical as it costs the price of a decent eyepiece but it can replace multiple eyepieces.

#86 tomchris

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Posted 12 October 2011 - 08:55 AM

As Jim stated, as long as you use a quality barlow lens, you should not notice any major negative effect.


Well- as you can see from my sign-off list, I think I've got a good amount of what I think are quality barlows. Thanks!!

#87 wprince

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Posted 12 October 2011 - 09:06 AM

They barlow quite well. Uae good barlow, of course.

Short eye relief doesn't bother me a bit, so I go for the "least glass" option....



IMO, for the $85.95/ea price, the only ones that make sense to me are the 7, 6, 5, and 4mm (and MAYBE the 9mm). Those for the really good nights on a tracking mount, where I don't want to use a barlow, and want the "least glass" option. For the 25, 18, 12.5, 9mm, for the price there are too many other options like TV Plossls, Antares elites, AstroTech Paradigms, even my 12.4mm Meade series 4000 plossl is excellent. Of course, some like the thought of owning the whole matching set of the UO orthos and nothing wrong with that! But from what I understand they are NOT parfocal.

I just bought a 4mm UO ortho from a well known member here at CN and am looking forward to a good night to try it.

#88 great_bear

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Posted 12 October 2011 - 12:39 PM

Orthos are like fine food - all this talk of them is making me want to buy a set again! :)

#89 Bart

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Posted 13 January 2013 - 12:19 PM

They perform much better in slow telescopes. At f/14.4 to f/16.7 they rock. At f/8.6 to f/10, they are still excellent. At f/7 they start to weaken even on axis. Faster than that, there are better choices.

Regards,

Jim


My ED80 is an f/7.5. The UO Orthos look fine to me when used with it. I guess it's just far enough from an f/7 that the views are still good. I was surprised that you said that they start to weaken.

#90 Sarkikos

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Posted 14 January 2013 - 11:02 AM

Jim,

Here's my "Ortho" collection, by the way:

Posted Image

My faves are the Pentax SMCs.

- Jim


Why no BGO's?

Mike

#91 junomike

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Posted 14 January 2013 - 01:59 PM

He had no need for the BGO's. The Pentax Or.'s have a similar FOV but are better for scatter control.
Also, with his coveted Brandon's, the BGO's would never see light anyway.

Mike

#92 Sarkikos

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Posted 14 January 2013 - 02:22 PM

JunoMike,

I don't know about that. I would have replaced the UO VT's from 5mm to 18mm with BGO's. In fact, that's what I did. The BGO's have better coatings, and I prefer the flat-tops. The Pentax Or's are something else entirely.

IME, BGO's and Brandons run nose-to-nose for planet/lunar. Also IME, the BGO's surpass the Brandons for deep sky because they are FMC instead of just FC. That's if transmission is important to the observer. Otherwise, the Brandons might show more structure in bright nebulae than the BGO's (not so much on the dimmer stuff). But I'd rather get that effect by putting a DSO filter on the BGO. YMMV

I have all the Brandons from 6-24mm, BGO 6/7/9/18 and only UO VT 4/25. The BGO 5 was sold after I acquired an XO 5.1. The BGO 12.5 was sold for a price I liked (otherwise I would have kept it). I have bino pairs of the Brandon 12 & 16, BGO 9 & 18 and UO VT 25. That pretty much sums up my viewpoint on these eyepieces.

:grin:
Mike

#93 SteveTheSwede

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Posted 14 January 2013 - 06:58 PM

While not generally accepted yet, your results certainly mirror my own field testing.


Actually, the theory is generally accepted.
Ask any refractor-owner who invested a small fortune in their latest top quality glass and they will happily tell tales about how their ridiculously expensive 4" refractors "out-performs" cheap 12" dobs right and left. Heck, let's make it 18" if the seeing isn't perfect, we all know how poorly those light-buckets perform when the seeing isn't perfect, right?
So the theory, I'd say, is very much accepted (just ask the right people).

Steve

#94 junomike

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Posted 14 January 2013 - 07:06 PM

Mike, I replaced my UO VT's with UO H.D.'s as I found them a tad better. I've also compared the Brandon's to the UO H.D.'s and found them to be more similar than different. However, others feel the Brandon's are superior for Star color saturation (which I'm not into).

In direct comparison (UO H.D.'s) on Planets and DSO's I found the Pentax Or. go deeper and offer a darker background. I only sold mine as I had the TMB SMC's as well. The difference wasn't huge, but noticeable.

Mike

#95 Sarkikos

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Posted 17 January 2013 - 08:31 AM

Steve,

Ask any refractor-owner who invested a small fortune in their latest top quality glass and they will happily tell tales about how their ridiculously expensive 4" refractors "out-performs" cheap 12" dobs right and left. Heck, let's make it 18" if the seeing isn't perfect, we all know how poorly those light-buckets perform when the seeing isn't perfect, right?


If you go down to an 8" or 10" Dob, though, I think the Dob would give the 4" APO a run for the money. This is especially true if the owner of the Dob collimates very closely and has worked on solving thermal problems.

Mike

#96 Sarkikos

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Posted 17 January 2013 - 08:42 AM

Mike,

Mike, I replaced my UO VT's with UO H.D.'s as I found them a tad better.


BGO's and UO HD's are near equivalent, so mirrors my strategy.

I've also compared the Brandon's to the UO H.D.'s and found them to be more similar than different. However, others feel the Brandon's are superior for Star color saturation (which I'm not into).


Agreed and agreed. I have more than a suspicion that many Brandonistas are double star enthusiasts. I like double stars, but I'm not an enthusiast. In my own personal list of preferences, doubles would fall behind planets, DSO and the Moon.

In direct comparison (UO H.D.'s) on Planets and DSO's I found the Pentax Or. go deeper and offer a darker background. I only sold mine as I had the TMB SMC's as well. The difference wasn't huge, but noticeable.


I've never tried Pentax Orthos or TMB SMC's, so I wouldn't know anything about them first hand.

I'm glad, though, that I have the XO 5.1 and 2.5. They are supposed to be about as good as the ZAO-II's. (I wouldn't know about those, either.) So far, the XO's have excelled at planets, Moon and double stars. I need to give them a try on DSO, maybe planetaries and galaxies. A little too high power for comfort when viewing the Moon, though, for me. But they gave me a great view of the Pup star!

Mike






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