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davidmcgo
sage
Reged: 10/09/04
Posts: 428
Loc: San Diego, CA
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Thanks Glen,
I forgot that Galilean's field is dependent on objective size and distance from eye. That would be much more limited by the exit pupil of the front binocular.
Dave
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holger_merlitz
sage
Reged: 02/08/04
Posts: 281
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I have finished a little write-up about the current Chinese version of the 2.3x40, which I recently received for testing. Here is the report:
http://www.holgermerlitz.de/opera2.3x40.html
Hope it might be of use to some of you.
Cheers,
Holger
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KennyJ
Reged: 04/27/03
Posts: 9980
Loc: Lancashire UK
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Thanks for yet another fine short review of a very interesting instrument , Holger .
Kind Regards
Kenny
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Two eyes and a preference to use both
Zeiss 7 x 42 BGAT
Captain's Helmsman 7 x 50
Nikon 10 x 42 Superior E
Swift Audubon Kestrel 10 x 50
Helios 15 x 70 Observation
Strathspey 20 x 90
Televue 76 APO
Zeiss 85 Diascope
Helios 102 f5 refractor
Various eyepieces barlows tripods mounts etc.
Panasonic Lumix DMC - TZ5 digital camera
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Wes James
Carpal Tunnel
Reged: 04/12/06
Posts: 2320
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Quote:
I've had a theory for several years now with regard to the optical illusion of objects not appearing as magnified as they truly are .
Kenny-
If you come up with very many more in-depth explainations that make such good sense on here, I fear they may rescind your "GRAND PRIZE for NON - INTELLECTUAL CONTRIBUTIONS" ! 
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Wes
Atlantic Beach, FL
Some bino’s from Miyauchi 5x32 Binon's up through Garrett 20x110 Signature's,
Some telescopes from a Stellarvue 80mm NHNG up through a couple of 8” reflectors…
And a wonderful 4.25" Delmarva Shiefspiegler!
Some good friends, made here on C/N.
Oh- several cats and a wonderful wife!
Anyone want a cat???? :-O
"When your work speaks for itself- Don't Interrupt" -Gamble Rogers
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KerryR
super member
Reged: 12/05/07
Posts: 103
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I've got a pair coming... I'm pretty excited about these. Be curious to pit them against my 5x32w Binons, though that's apples to oranges, I suppose...
I think it could be fun to get the nebula filters for these, if/when they become available. I talked to Blue Planet, and he (I've forgotten the owners name) said he's still working on finding a machinist to do the mill work, so they're not available yet, nor does he know what the price is expected to be, nor the release date...
I suppose I'll have to try taping (or something) a 2" UHC filter on one side and a 2" O III (Probably too dark for this apeture) on the other,... I have 2 1.25" celestron UHC filters, which I might be able to affix to the eyepieces, but it sounds like there's not enough eye relief to make this possible. Maybe with the eye-cups removed?? Have to see when I get them. Anyone tried anything like this yet?
Thanks for the review, Holger
Kerry
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GlennLeDrew
sage
Reged: 06/18/08
Posts: 325
Loc: Ottawa, Ontario, Canada
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KerryR,
It's not the aperture that imposes a limitation to the use of narrow bandpass filters, but exit pupil. The Owl Eye has a rear eye lens clear aperture of >8mm, allowing you to use your eye's full pupil diameter. Therefore the really narrow filters are perfectly OK!
===================
I did some more in-depth examination with my Owl Eyes last night. As already noted, with the rear eyepiece cover threaded off, I can get my eyes sufficiently close to see the full field. For example, The full length of the Big Dipper fits in with no trouble, and Scorpius comes really close to squeezing in. Another nice view was provided by the "kite" figure of Bootes and Corona Borealis, again, in the field all at once.
Comparing the apparent field (which necessarily has a fuzzy edge, being a Galilean system) against a 5x21 having a 60 degree afov, I'd say it's pretty close. According to the numbers, 2.3X times 28 degrees = 64 degrees. And it might just be that large.
And as already pointed out, when the eye is centered properly, the stars are beautifully sharp out to a surprisingly large off-axis distance. I reaffirmed the important of centration of the eye, and indeed, it is folly trying to assess star sharpness well off-axis by looking away from the field center because of the now incorrect eye placement. When looking on-axis, the stars are sensibly sharp to the "edge" of the field.
I also verified that a Galilean design does NOT make a good auxilliary telescope to place behind another instrument's eyepiece. The portion of the field seen is VERY small!
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Home-made 11X50 right angle bino, 8.1 deg. FOV
Modified 26X100 bino, 3.5 deg. FOV
Mediocre minds discuss people. Good minds discuss events. Great minds discuss ideas.
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KerryR
super member
Reged: 12/05/07
Posts: 103
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Glenn,
When you removed the rear ep cover, were the lenses in any danger of falling out? I suppose I could just wait until mine arrive and check it out for myself...
I wonder if I could remove my 1.25" UHC filters from their mounts, remove the Owl Eyes eyepiece cover, insert the UHC filters (now reduced to glass disks), and replace the rear covers to hold the filters in place?
Maybe this is a little overboard... Just thought it might be cool...
Kerry
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GlennLeDrew
sage
Reged: 06/18/08
Posts: 325
Loc: Ottawa, Ontario, Canada
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When the rear pieces are removed, the outer barrel can fall off. But the eyepiece assembly itself stays in because it has a multi-start thread for focusing. The outer barrel has a small notch to align with a pin on the eyepiece barrel, which then allows for focusing. The gap under the outer barrel is small, and a tab of tape can be used to provide a good friction fit, and can be placed so that it's invisible.
In case I didn't stress it enough, daub some black paint on the exposed ground edges of the eye lenses. There are two surfaces requiring this:
1) Most importantly, the flat ring which immediately "frames" the ~8.5mm useable aperture, and
2) the conical section outside of this.
This will eliminate the vast majority of annoying scattered light.
There just ain't any room to insert filters behind the eye lens. Moreover, the filter would only force your eye farther back and hence reduce field, and it would be covered with eyelash marks in no time.
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Home-made 11X50 right angle bino, 8.1 deg. FOV
Modified 26X100 bino, 3.5 deg. FOV
Mediocre minds discuss people. Good minds discuss events. Great minds discuss ideas.
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KerryR
super member
Reged: 12/05/07
Posts: 103
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I recieved mine Friday, and, miraculously, the sky was clear the same night, which is a big deal here in Michigan.
I was astounded at how sharp and clear the optics are, and how wide the field is-- Deneb to Albiero (just barely), and most of it usable. These kind of make my Myauchi 5x32w' obsolete, at least for this sort of wide field experience. The 2.3x40's are sharper accross more of the field (thought the 5x32's are sharper in the middle...)
I think these may be the 'funnest' astronomy purchase I've ever made. If ever there has been a bino for laying in lounge chair and just looking at the sky for the fun of it, these are it!
The construction is really nice. I couldn't see any 'glossy' edges on the lenses, and even the daytime view shows no scattered light or 'fuzzing' at the edges. The curvature of field is surprisingly subtle, too. I'd say 85% or so of the 25ish degree field is sharp. Definitely need to be sure the binos are on axis with your eyes' lenses. The coma is so obvious when they're not on axis that it's easy to correct for though.
I love these binos!
Kerry
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Swedpat
Pooh-Bah
Reged: 02/18/05
Posts: 1006
Loc: Boden, Sweden, Scandinavia
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Interesting to read your experience Kerry,
Last week I ordered two examples of them and will give my impression when I have tried them.
Regards, Patric
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*2,3x40 Constellation View Wide-Bino
*Leica Ultravid 8x20 BR
*Leupold 6x30 Yosemite
*Leupold Katmai 6x32
*Swarovski SLCNew 7x42B
*Bresser (Lidl) 10x50
*Oberwerk 11x70
*No name (Kunming) 15x70
*Scopos ED APO 66
*Celestron Accessory kit, Vixen LV 20,10,5mm
Psalm 19:2
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