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Why does my 15x60 seem less sharp? (1 Viewer)
- Thread starter tenex
- Start date
WJC
Well-known member
Zeiss 15x60.
Just after midnight this morning I looked at Sirius.
It was at about 18 degree elevation above a heated rooftop.
Hand held, Sirius was dancing around madly in a rainbow of psychedelic colours.
I was tired so hand holding was worse than usual.
The only thing I could glean was that the binocular is very well aligned and has no astigmatism.
04.57 UT this morning.
Binocular braced but hand held.
Jupiter about 15 deg elevation.
Unfortunately involved in branches of the old oak tree.
The disc looked soft. I think because of spherical aberration.
There was a small amount of false colour around the limb.
Equatorial diameter 35.7 arcseconds.
The observation is not very reliable because of tree branches.
Jupiter barely gets above 20 deg elevation even when south here.
I was surprised to see only Callisto far to the left and no other moons.
If I had used the Canon 18x50 IS it is likely I would have seen the moon Io close to Jupiter's limb.
08.27 UT wind 190 deg 1 kn 9km mist cloud scattered 3,800ft broken 30,000ft minus 2C TDP minus 2C 1030.5 hPA
Just after midnight this morning I looked at Sirius.
It was at about 18 degree elevation above a heated rooftop.
Hand held, Sirius was dancing around madly in a rainbow of psychedelic colours.
I was tired so hand holding was worse than usual.
The only thing I could glean was that the binocular is very well aligned and has no astigmatism.
04.57 UT this morning.
Binocular braced but hand held.
Jupiter about 15 deg elevation.
Unfortunately involved in branches of the old oak tree.
The disc looked soft. I think because of spherical aberration.
There was a small amount of false colour around the limb.
Equatorial diameter 35.7 arcseconds.
The observation is not very reliable because of tree branches.
Jupiter barely gets above 20 deg elevation even when south here.
I was surprised to see only Callisto far to the left and no other moons.
If I had used the Canon 18x50 IS it is likely I would have seen the moon Io close to Jupiter's limb.
08.27 UT wind 190 deg 1 kn 9km mist cloud scattered 3,800ft broken 30,000ft minus 2C TDP minus 2C 1030.5 hPA
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tenex
reality-based
Fleurviola: Perhaps disassembly and cleaning of all optics would improve the image.
WJC: It is disheartening that it has taken 19 posts to get to the culprit.
Perhaps you haven't noticed that the culprit in this case was already identified some posts ago? It was me. (Thanks Hermann, Lee, Henry) This binocular has not been to Afghanistan.
[Edit] This is still a very fine 15x60. I must just have been having a bad day on Sunday somehow, and atmospheric conditions may have contributed to some extent. Today I'm having no trouble focusing, and am back to the experience I recall, a beautiful view with a little jitter unless I stabilize it somehow. Which is good, because that's what this bino is meant for... and I'm not over the hill quite yet.
WJC: It is disheartening that it has taken 19 posts to get to the culprit.
Perhaps you haven't noticed that the culprit in this case was already identified some posts ago? It was me. (Thanks Hermann, Lee, Henry) This binocular has not been to Afghanistan.
[Edit] This is still a very fine 15x60. I must just have been having a bad day on Sunday somehow, and atmospheric conditions may have contributed to some extent. Today I'm having no trouble focusing, and am back to the experience I recall, a beautiful view with a little jitter unless I stabilize it somehow. Which is good, because that's what this bino is meant for... and I'm not over the hill quite yet.
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The old Oberkochen porros can suffer from hazing of their optical surfaces, apparently due to outgassing. I've seen this in both of those I've handled and other users such as Tobias have commented on it. 15x magnification = 15x more hand shake - something you would need to take into account in assessing its optical performance - but it might not be a bad idea to have your pair professionally cleaned in any case. If it's build quality you are after those old Zeiss Wests definitely have it.
WJC
Well-known member
Hi, Tenex:
I certainly didn't intentionally miss something you said. However, in going back through the thread from the beginning, I see you have talked about resolution, aberrations, jitters, and other things but have failed to see where you talked about microscopic particulates being deposited on optical surfaces as being a "culprit" in robbing the image of its "crispness." Could you share the number of that post with me that I might apologize, again? :cat:
Thanks,
Bill
PS Patudo, I think you will find the problem relates more to those microscopic particulates than outgassing. Not all adhesives cause outgassing problems and I would hope professionals would know which ones to avoid.
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Glad you feel you have got a handle on what was causing your suspicions of 'unsharpness' now. And for goodness sake don't use the shaking of a 15x60 as a measure of how far up the hill or over it you are. That is a big bino and a monster magnification to hold steady at any age.
Lee
WJC
Well-known member
tenex
reality-based
I agree. I've used 10x regularly for decades, but if I look closely I can see a little jitter I usually manage to ignore. I think about this every time I hear someone say "you can handhold 7/8x at best, not 10"... or whatever. Any bino of useful magnification will have some unsteadiness in handlheld viewing for any length of time. It's just a question of how much is tolerable for a given purpose.
By the way, I often wonder which factor accounts for more individual variation in answering that question: physical steadiness of the arms, or the brain's ability to compensate for an unsteady image? (And lately, which declines more with age...!)
That's a really interesting link denco, and there's also plenty of evidence (see the comments in the 8.5x42 thread) that indicates that coatings have slowly but steadily improved. In using my 8x30 Oberkochen (single-coated) I've found its resolution is excellent at relatively short distances, 150m or so - city birding gives you lots of opportunities to look at lettering of different sizes on advertising boards and so on at varying distances - but seems to fall off the further away my targets get, even accounting for distance. I'm not sure whether this is due to less advanced coatings, the binocular's optical design or simply the city smog in London, although I've used it in on both good and poor visibility days. Leaving aside the other perfectly valid reasons why image quality of a hand held 15x could be degraded, I do think modern T* coatings on the 15x60 (by all accounts a very impressive glass, which I'd certainly like to look through) would likely result in a noticeably better image yet.
I can't use a 15x hand held unsupported for long - if using hand-held I would recommend propping your elbows on a wall, fence or similar, or sitting down and bracing your elbows on your knees. It makes a huge difference.
