edwincjones
Post Laureate
Reged: 04/10/04
Posts: 4119
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a final thought-these should be great for Messier Marathons with their wide FOV - just point, see the M "speck" and go to the next M object.
seems like cheating, but they were seen,
edj
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n w arkansas
Binocular, Solar, General Amateur Astronomy
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CESDewar
GorillAstronomer
Reged: 01/16/05
Posts: 1692
Loc: Morganton, GA, USA
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Hey, this gives me another thought for something other than a sequential Marathon...
What is the greatest number of Messier objects you can see in one FOV? Of course as you increase the FOV, you decrease the magnification, making it hard to see the fainter objects -- so pointing it at Virgo might not be the best strategry, although my guess is that'll still be the winning placement. If so, we'll make it apart from the Virgo galaxies!
I'm wishing now I did that while all the Southern eye candy was still up in the sky (it's getting rather low now), but it should be possible to see M16, 17, 18, 19, 25, 24, 23, 21, 20, 8 (maybe even 28?) in the same FOV! Of course there's a question on some Messiers like 16 which involve a cluster with nebulosity - the cluster may be obvious, but the nebulosity much less so in tiny Binos like the 5x32's...
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edwincjones
Post Laureate
Reged: 04/10/04
Posts: 4119
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interesting idea
edj
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n w arkansas
Binocular, Solar, General Amateur Astronomy
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edwincjones
Post Laureate
Reged: 04/10/04
Posts: 4119
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terestrial use at Grand Canyon--in two words
"not impressive".
As mentioned above, I took the miyauchi 5x32s to the Grand Canyon this past week and I was not impressed:
the 13 degree FOV was not enough for the canyon,
the 5x was not enough to adequately see the golden eagle flying overhead
I will keep them in my truck for convenience, and use primarly for the night sky.
compromises have limits,
edj
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n w arkansas
Binocular, Solar, General Amateur Astronomy
Edited by edwincjones (11/25/07 06:26 PM)
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Wes James
Carpal Tunnel
Reged: 04/12/06
Posts: 2310
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Quote:
compromises have limits,
edj
Darn it- *sigh* 
Wes
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Ortho2000
sage
Reged: 01/09/07
Posts: 278
Loc: Northern Virginia
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I have considered buying a pair of these wide angle binoculars, but apparently there are quite a few German reviews which question the specifications . The published close focus of 4 meters is more like 5.5 m. The claimed TFOV of 13.2 degrees is more like 11.8. with the 231/1000 meter spec going down to something like 207/1000 m.
Another fellow claimed the prism coatings were questionable, and that the unit did not feel good in his hands because of the sharp corners.
I am basically looking for a pair of really wide angle low power binos that I can use to stare at an entire large constellation. Maybe I will just hang with my ancient Magnesium Body Tasco 7x50 that claim 578 feet at 1000 yds.
Any additional comments would be welcomed.
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Ancient Orange Astro C-90 Celestron
Ancient Meade 2080 8 inch Schmidt-Cassegrain
Vixen ED115S APO 4 1/2 in Refractor & GPD2 Mount.
Meade ETX125 Mak
Unitron 60 mm F/15 Equatorial Refractor
Unitron 100 mm F/15 Equatorial Refractor
Stellarvue 80mm NHNG on Vixen Portamount
Meade 80mm DS-80AT F/11 GoTo Refractor (yardsale)
Vixen 16x80, Zeiss 10x40, Tasco #124 7x50 WA, Leitz 8x20 Roof Prism, Olympus 10x25 Roof Prism
Lunt 60mm Solar Scope on Order
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edwincjones
Post Laureate
Reged: 04/10/04
Posts: 4119
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I have had the miyauchis for 6 months now, and am still happy with them.
edj
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n w arkansas
Binocular, Solar, General Amateur Astronomy
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EdZ
Professor EdZ
Reged: 02/15/02
Posts: 12147
Loc: Cumberland, R I , USA42N71.4W
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Quote:
Maybe I will just hang with my ancient Magnesium Body Tasco 7x50 that claim 578 feet at 1000 yds.
Are you sure that was 578 ft and not 378 ft. 578 ft would make them by far the widest Afov binocular I've ever heard of. It would make them a full 50% wider than any 7x50 I've ever measured!!!
edz
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Teach a kid something today. The feeling you'll get is one of life's greatest rewards.
member#21
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Joe Ogiba
Pooh-Bah
Reged: 02/14/02
Posts: 2969
Loc: NJ USA
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Tasco 124 Extra Wide-Angle 7x50 578ft @1000 yds
BTW my Orion Expanse 7x32 UWA binoculars are rated at 14° AFOV and 98° AFOV.
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EdZ
Professor EdZ
Reged: 02/15/02
Posts: 12147
Loc: Cumberland, R I , USA42N71.4W
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I guess I need to take that back. I had forgotten about my acient pair of Empire model 250 (J-B146) wide angle 7x50. They are claimed to be 10°, 525ft/1000yds. They actually measure 9.3° (488ft/1000yd.), for a typical Afov=65°.
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Teach a kid something today. The feeling you'll get is one of life's greatest rewards.
member#21
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Ortho2000
sage
Reged: 01/09/07
Posts: 278
Loc: Northern Virginia
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Hi EDZ and Joe,
Thanks for your comments, especially on the Tascos. The problem is that my Model 124 Tasco is about 40 years old now.
Given all the progress in ED glass and coating technology, as well as eyepiece design by the likes of Nagler and others, in 2008 where does a person turn to for a truly super wide angle low power " survey of the constellation" style binocular. The previously mentioned 2.3x30 units have non-prismatic design as well as issues with exit pupil and eye relief. Based on the reviews I have read here on CN, the 7x32 "Expanse" series, marketed by Vixen, Orion, Celestron, and maybe a few others, seem to have really really tight eye relief, and very modest optical quality. It, like the Tasco, is no longer available.
Bushnell does make a 4x30 xtra-wide-angle clam shaped binocular claiming FOV of 900 feet at 1000 yds, 6 mm exit pupil, and 10 mm of eye relief. The B&H webpage sites roof prism design. Therefore, the Miyauchis I guess are the best thing going then as of May 2008 ?
Hey, what about that new Fujinon 6x30 ED glass compact binocular with the Nagler Ethos eyepieces ? Just kidding..
Paralysis by analysis. That's where I am now. So, does anyone have any other super wide angle binocular recommendations ?
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Ancient Orange Astro C-90 Celestron
Ancient Meade 2080 8 inch Schmidt-Cassegrain
Vixen ED115S APO 4 1/2 in Refractor & GPD2 Mount.
Meade ETX125 Mak
Unitron 60 mm F/15 Equatorial Refractor
Unitron 100 mm F/15 Equatorial Refractor
Stellarvue 80mm NHNG on Vixen Portamount
Meade 80mm DS-80AT F/11 GoTo Refractor (yardsale)
Vixen 16x80, Zeiss 10x40, Tasco #124 7x50 WA, Leitz 8x20 Roof Prism, Olympus 10x25 Roof Prism
Lunt 60mm Solar Scope on Order
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Joe Ogiba
Pooh-Bah
Reged: 02/14/02
Posts: 2969
Loc: NJ USA
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I have four 7x binoculars and the the Zeiss 7x42 FL T* have the widest AFOV at 60° or 8.6° FOV of all the premium top of the line binoculars and look even brighter than my Celestron Oceana 7x50 WP-IF/RC binoculars.
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Pentax PF-80ED
Meade 102ED APO
Orion 120ST
Apex 127
CR150
C9.25
XT10
Zeiss 7x42 FL
Canon 10x42L IS WP
15x50 IS
12x36 IS II
Garrett Optical 28x110 HD-WP Signature Series
Oberwerk BT-80 45
Apogee RA-88-SA
Denk II Power x Switch binoviewer w/13mm Ethos, 20mm Pentax XW's, 20mm Widescan III's.
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CESDewar
GorillAstronomer
Reged: 01/16/05
Posts: 1692
Loc: Morganton, GA, USA
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Quote:
So, does anyone have any other super wide angle binocular recommendations ?
Carson 8.5x42mm have FOV of 578' at 1,000 yards which comes out to an 11.1° TFOV and an amazing, ethos-like 94.5° AFOV. The specs look pretty accurate - I tested on several star fields and found one with two pretty bright stars separated by 10.5° and they were both readily visible at the same time.
The ER is definitely sort - you do have to jam your eye's into the eyecup to take in the full FOV and of course there's a pretty good amount of edge falloff - but the center sharpness is not bad at all. These would be useless with eyeglasses. And not all viewers are able to take in that wide a AFOV. I have no difficulty seeing the field stop in my Ethos  , but I do know that there are other observers who can't do that at all. It's clear there are significant differences in the quality of peripheral vision that people have.
The TFOV looks very close to my 5x32 Binons, with substantially more magnification, but there's no question the Binons are a lot more comfortable in terms of taking in that FOV. But I still think that for $149, they are a good value for people looking for really wide-field binoculars (and who don't wear glasses).
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DJB
Pooh-Bah
Reged: 02/23/05
Posts: 1181
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Hi EdZ,
While checking out eBay, I find 7x50 WA binoculars quite frequently. Of course, as you know, the 7x35s offer a generous FOV on quite a few inspections (for what it is worth).
I also have an Orion Expanse 14* binocular. No, it is not great, as I believe Kanny has alluded to. But, just the initial impresson is truly amazing. It's more of a fun thing, in my opinion.
I suppose we have to go back to the WWII WA binocs manufactured by the likes of B&L and SARD. Don't I wish.
Best regards,
Dave.
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EdZ
Professor EdZ
Reged: 02/15/02
Posts: 12147
Loc: Cumberland, R I , USA42N71.4W
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Making a wide angle binocular in a 7x50 is a very different problem than doing it in a 7x35. In a 7x35 or 7x42 it's easy. The eye pieces are a shorter focal length and there is more room to make a wider field stop. That room diminishes in a 7x50 and it becomes much harder to squeeze a wider field stop into the eyepiece barrel. To accomodate extreme wide field 7x50s most likely means they are faster f# binoculars than narrower Afov. That's necessary to make the wider fov.
Just so you can understand this problem, take three binoculars for example a 7x35, a 7x42 and a 7x50. if all were f/4 then the eyepieces would be 20mm, 24mm and for the 7x50s they would be 28.5mm. It's easier to make a 20mm/70° eyepiecce than it is to make a 28mm/60° eyepiece. So comparing wide field 7x35s or 7x42s to a WF7x50 is comparing apples and oranges.
The designer can help accomodate the wider fov in a 7x50 by making the lens faster, perhaps f/3 or f/3.5, but that begins to introduce other problems.
An 11° 7x50 either has an eyepiece that has about a 38mm field stop to accomodate f/4 (not very likely since that's not too dissimilar from many 2" eyepieces used for telescopes), or it is getting closer to being down around f/3.3 and it has a more reasonably sized eyepiece.
edz
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Teach a kid something today. The feeling you'll get is one of life's greatest rewards.
member#21
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DJB
Pooh-Bah
Reged: 02/23/05
Posts: 1181
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Hi EdZ,
That is a very good synopsis provided by you. Perhaps this will help many here understand the design (on paper) vs. the pratical implemention vs, cost. Thank you.
Best regards,
Dave.
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GlennLeDrew
sage
Reged: 06/18/08
Posts: 310
Loc: Ottawa, Ontario, Canada
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Edz, et al,
A friend owns a Tasco Model 124 7x50, and we've had them apart. The extremely wide true field is achieved via use of a single-element, weak, positive meniscus lens threaded into the prism shelf almost up against the rear prism. The lens therefore acts like a telescompressor.
The eyepieces have 27mm diameter field stops, if memory serves. Taking the compressor lens out yields very close to 10X, with the necessary bit of refocusing.
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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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GlennLeDrew
sage
Reged: 06/18/08
Posts: 310
Loc: Ottawa, Ontario, Canada
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Forgot to add... the apparent fov of the Model 124's eyepieces is certainly 80 degrees, possibly a bit more.
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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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EdZ
Professor EdZ
Reged: 02/15/02
Posts: 12147
Loc: Cumberland, R I , USA42N71.4W
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I would guess then that the effective focal lenght is less than f/3.
edz
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Teach a kid something today. The feeling you'll get is one of life's greatest rewards.
member#21
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