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Message: <blockquote data-quote="Kevin Purcell" data-source="post: 1269872" data-attributes="member: 68323">Day 2: Night TestsI noticed we had a clear night at 11pm with Jupiter just past the meridian and the moon just before it. The separation between the (almost) full moon and Jupiter was a bit over 10 degrees. Could make an interesting test.So I took my bins outside (to a local P-patch). The local lighting is not bad (but there are several bright local lights but nothing along the line of sight.) In addition to the usual test bins I also too my Minolta Compact 8x25, Orion Explorer 10x50 (a $100 astro bin, Made in Japan in late 1990s, 5.3 degree FOV, fully single coated, BaK4 porro, with rather a flat field, not great eye relief) and a Chinese Meade 10x50 (fully single coated, BK7 porro, $30 from Amazon but not that bad for a cheap bin). I've used both of the latter for binocular astronomy.All the observations were made with handheld binoculars.Jupiter TestsAll the binoculars resolved Jupiter into a disc. None revealed any banding on the disc.Star ImagesNot sure which stars I used (skyglow and moonlight were bad) but I suspect it was Sagittarius (to the west of Jupiter at about the same elevation). Results in order of sharpness (most to least).1. Celestron Ultima DX 8x32 (best crisp star points)2. Leupold Yosemite 6x30 (pinpoints)3. Vortex Diamondback 8x42 (not quite as crisp)4. Vortex Hurricane 8x28 (not as crisp as Diamondback and fewer of them)5. Minolta Compact 8x25The Orion Explorer 10x50 was about the same as the Diamondback.Counting the Moons1. Orion Explorer 10x50 - 3 moons2. Celestron Ultima DX 8x32 - 3 moons3. Vortex Diamondback 8x42 - 2 moons (but perhaps 3 occasionally)4. Leupold Yosemite 6x30 - 2 moons5. Meade 10x50 - 2 moons6. Vortex Hurricane 8x28 - 2 moons7. Minolta Compact 8x25 - 1 moonI didn't realize until I came back inside and checked Jupiter's moons on Sky and Telescope web site that Calisto was in shadow whilst I was doing the observations so the maximum number of moons I could see was 3 (and not 4).As you can see from the attachment Europa and Io were close together on the lefthand side (east) of Jupiter making a close "binary". Ganymede was on it's own on the righthand (west) side of Jupiter with a rather greater separation from the planet. A rather useful configuration to test the bins with.The Orion 10x50 easily found the 3 moons. The DX had a smaller aperture (so more skyglow) but better transmission and less shake helped. The Diamondback could easily see two moons but every once in a while I'd see the third moon. Not sure if this was a difference in shake or contrast oe brightness or a combination of those factors. The Yosemite was sharp but I think lacking in the magnification to "split" the moons plus it suffered most from skyglow.Close to downtown Seattle the light pollution is rather bad and favors higher magnifications that "dilute" the sky glow compared to star-like targets.Stray LightWhilst looking at the moons for Jupiter it was clear that stray light was coming from the almost full moon around 10 degrees or so to the east. That's a pretty tough test but it showed differences in how the bins hadnle stray light more clearly than daytimes tests (with a reasonable dark background you can see the stray light more clearly).1. Celestron Ultima DX 8x322. Leupold Yosemite 6x302. Vortex Diamondback 8x424. Vortex Hurricane 8x285. Minolta Compact 8x25The DX was clearly the best though some stray light could be seen. The Yosemite and Diamondback were similar in the amount of stray light though it looked a bit different in each case. The Hurricane was clearly suffering badly. with a large almost half field cresent of light on the opposite side of the field to the moon. As I swung the Hurricane around the moon I could see the crescent rotate. Not good at all.Once again I see the porros leading the testing with the Yosemite losing out at least partly because of magnification. The roof follow up. And my old Minolta is rather outclassed.</blockquote>

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