Michael Gilmer - Member of the Meteoritical Society & Collector of Falling Stars.
☄ ⒼⒶⓁⒶⒸⓉⒾⒸ ⓈⓉⓄⓃⒺ - www.galactic-stone.com
MarkLeica 8x20; Nikon Action 7x35; Vixen Apex Pro 8x42; Orion 15x63; Docter Nobilem 15x60WO Megrez II 80 FD / APM 107mm f/6.5 / Mewlon 210 on DM-6 + Berlebach Planet
Milton Wilcox R.I.P
Quote:Ultra 15x70 - Some first observations.I did manage to get a few minutes of daylight tests in, but not enough time. Incomplete results so far on USAF resolution tests, will be reported later. However, one noticable difference in actual vs specified became apparent. The specified close focus of this binocular is 10 meters. That's 33 feet. With eyeglasses correct vision, my sample has an actual measured close focus of 120 feet or 36 meters!Full field of view spans from Gamma (Y)Del to Eta (n)Del, almost exact. This is 4.35°. Close to the specified 4.4°, this is wider than the 4.0° Fujinon and about the same as the Oberwerk 2003 15x70.Collimation was dead on. Checking numerous times on a 1 arcminute double, I could not even see any degree of minor mis-adjustment. Using a 1 arcmin double at 15x, I would easily be able to see even if it were off by 20-30 arcseconds. These aren't even off by 15 arcseconds. Images merged completely. The field of view in the barrels overlaps nearly perfectly.I wish the eye relief could be a little longer for us eyeglass wearers. I cannot see the outer right edge with my R eye and I cannot see the outer left edge with my L eye, but together with both eyes I can see to both edges. The L eye can see the far right edge of field and the R eye can see the far left edge of filed. It seems as though I can see the entire fov, but the field stop is somewhat blurred. When I took my glasses off to have a quick look, I noticed the field stops more distinct. These are similar to how I use and see with the Fujinons.Stars begin to show minor but acceptable radial elongation (elongation parallel to field edge) at 55% to 60% out from center. It begins to get unacceptable about 70-75% out. Significant radial elongation and coma really distort stars at 80-85% out. This may be a combination of astigmatism and coma. I did not identify any spherical aberration. No bloated circular stars seen. Under a mag 5.4 sky that was intermitently cloudy and then very clear, stars of mag 10.1 to 10.4 were seen readily. Fainter stars at first seen with averted vision could later be seen directly. Five faintest stars seen were all between mag 10.7 and 10.83. No attempts at mag 10.9 or mag 11.0 were seen. This puts faintest stars right in line with the other Oberwerk 15x70.I could see some minor CA on Vega, some blue with Vega on-axis. A hint of false blue color was seen on Altair. No color was seen on Deneb. No off-axis color was seen on any of the three. All three of these very bright stars showed the distinct spiking often seen on bright stars. No other objects viewed throughout the remainder of the night showed any of these affects.As far as true color, Mu Cephei showed up as a distinct orange color.I viewed about 20 deep sky objects. Several that were nice to see were M71, a prominet but small hazy patch; M57, still very small but obviously not a star, no dark center; the North America nebula, not distinct, but some areas noticed, an indicator of good contrast; the Double Cluster, the Owl 457 and Stock 2 all pretty sights; NGC 7789, a few suspected resolved, also an indicator of good contrast.An enjoyable first night out!edz
Quote:so the bubble is bursting...
Quote:I think what may be the most significant strength of these binoculars so far is mechanically the apparent ruggedness
Quote:Perhaps a "tripod tip over" test is needed
Quote:UO Kunming website claims "sharp to edge" which is surely optimistic.
Jeff Morgan - Wile E. Coyote School of Telescope Making
Quote:but the name Ultra Series 8 Premium Grizzley could surely be improved upon
Quote:Some time back, a newcomer started bashing the Fujinon F-series—as if that would not raise the eyebrows of any knowledgeable observer—and then started the line of superlatives to support his choice of cheap Chinese binoculars. When this kind of thing starts, whether the person is pulling stuff off the top of his head or from the sales literature, it can cause problems for the unwary.
They're not. mariner is series 3. What gave you the idea the mariner was the same series as the ultra?
Quote: am I correct to read that the Mariner series 3 is towards the top of the sharpness list?
Quote:However, assuming the average of the readings, the percentage of sharp field almost always matches the Ultra.
Quote:Stars begin to show minor but acceptable radial elongation (elongation parallel to field edge) at 55% to 60% out from center. It begins to get unacceptable about 70-75% out. Significant radial elongation and coma really distort stars at 80-85% out. This may be a combination of astigmatism and coma. I did not identify any spherical aberration. No bloated circular stars seen.
So, it is your opinion, after these initial tests and observations, that the amount of usuable sharp field is about the same in the U15x70 as the GO 20x70?
Would the gain in 5x magnification have any impact on this criteria?
Also, you did not mention any issues regarding eye relief (not since your intial impressions), so I take it that there are no issues in this area? You wear glasses while observing, as do I, and this is always a concern for me.
Stars begin to show minor but acceptable radial elongation (elongation parallel to field edge) at 55% to 60% out from center. It begins to get unacceptable about 70-75% out. Significant radial elongation and coma really distort stars at 80-85% out. This may be a combination of astigmatism and coma. I did not identify any spherical aberration. No bloated circular stars seen.
Did your followup observations shed any light on this optical issue? This is one area of concern for me since one of my first priorities is the aesthetic of the view.
Is the effect uniform across the entire spectrum of point source magnitude, in other words, is the effect more pronounced on bright stars and less so on faint stars or is it equal in all respects?
Thanks for all your patience and attention to detail while doing these informative evaluations.
Clear dark skies...
Quote:The Ultra 15x70 spotted two different stars of mag 10.83 and 10.84, but could not see 10.93 after numerous tries. Mag 9.8 to mag10 stars were seen constant.
The Fujinon 16x70 missed the mag 10.83 star, but saw the mag 10.84 star and also saw a mag 10.93 star.
Quote: Odd about not seeing the 10.81 in the Fuji's... might this have something to do with spectral transmission curves? The predominant color of that 10.84 star matching better with the Ultra than the Fujinon? I can't come up with any other explanation. Would that then be a coating issue?
Quote: never had the pleasure of looking through some really nice glass