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what can I do with 8x42 binoculars?
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#12
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what can I do with 8x42 binoculars?
John C. Polasek wrote:
On Mon, 4 Aug 2008 06:11:56 -0700 (PDT), wrote: I have recently bought a pair of Nikon ATB Monarch 8x42 binoculars mainly for outdoor use and wildlife observation..... Is 8x42 really useless for night sky observation on can I see some planets besides the Moon? .... You may be interested to know that your eye, in night accommodation, opens to 7 mm. The exit pupil or "light spot" from an 8x42 = 42/8 = 5mm. The exit pupilfrom a 10x70 is 70/10 = 7 mm. Any exit pupil larger than 7 mm will be of no value. The intensities are as 7^2/5^2 = 49/25 = 2:1. For the mathematically challenged amongst us, was that a yes or no to the query? Are you saying a pair of 10x80's will be no good, and a pair of 7x30 will be better? Thanks Alan. -- To reply by e-mail, change the ' + ' to 'plus'. |
#13
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what can I do with 8x42 binoculars?
"A.Lee" wrote in message
... John C. Polasek wrote: On Mon, 4 Aug 2008 06:11:56 -0700 (PDT), wrote: I have recently bought a pair of Nikon ATB Monarch 8x42 binoculars mainly for outdoor use and wildlife observation..... Is 8x42 really useless for night sky observation on can I see some planets besides the Moon? .... You may be interested to know that your eye, in night accommodation, opens to 7 mm. The exit pupil or "light spot" from an 8x42 = 42/8 = 5mm. The exit pupilfrom a 10x70 is 70/10 = 7 mm. Any exit pupil larger than 7 mm will be of no value. The intensities are as 7^2/5^2 = 49/25 = 2:1. For the mathematically challenged amongst us, was that a yes or no to the query? Are you saying a pair of 10x80's will be no good, and a pair of 7x30 will be better? Thanks Alan. I'm no expert, Alan, but the way i read it, John is saying that because the human eye dilates to no more than 7 mm, it might cost more for a larger than 7 mm "light spot" or "exit pupil", and it would be no better than one with the 7 mm exit pupil. And yet the 7 mm would be larger than the one you mention, 30/7 = 4.3, so the 7 mm would be better than that, yes. So if you have to pay a little more for the 7 mm, it would be better than the 4.3 mm. But if you had to pay more for an 8 mm, you're better off with a less costly 7 mm. HTH happy days and... starry starry nights! -- Indelibly yours, Paine Ellsworth P.S.: Thank *YOU* for reading! P.P.S.: http://painellsworth.net |
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what can I do with 8x42 binoculars?
I think that there is a lot of confusion over exit pupil size, with both
binoculars and telescopes. For a good general discussion of the issues, see: http://www.skyandtelescope.com/equip...tml?page=4&c=y With binos, there are the added factors of size/weight, and the benefits of an oversized exit pupil for ease of eye positioning. I think the bottom line is that there are no hard rules here, and that obsessing over exit pupil size is pointless. Every aperture/magnification/exit pupil/optical-mechanical package has advantages and disadvantages. Your 8x42 binos will capture some number of objects as well as or better than every other instrument! Enjoy them. Dennis |
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what can I do with 8x42 binoculars?
On Aug 4, 4:11 pm, wrote:
@ Saul: I expect that you Celestron 8x56 can get a *lot* more light than my Nikon ATB Monarch in 8x42. I did consider the Nikon ATB Monarch in 8.5x56 but I just could not afford them (I got my 8x42 at 200 bucks, so I can hardly complain about the price). I suppose that 42 vs. 56 is a huge difference, but I hope to be able to afford some decent x56 or even x70 one day :-) Your binoculars should be fine to use for astronomy. Rather than getting some larger 70-80 mm binos, think more in terms of a simple 150 mm or larger Newtonian telescope for a similar price. |
#17
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what can I do with 8x42 binoculars?
"Dead Paul" wrote...
in message ... . . . -- ___ _______ ___ ___ ___ __ ____ / _ \/ __/ _ | / _ \ / _ \/ _ |/ / / / / / // / _// __ |/ // / / ___/ __ / /_/ / /__ /____/___/_/ |_/____/ /_/ /_/ |_\____/____/ ___ ______ ___ ___ ___ _ ___ / _ \/ __/ _ | / _ \ / _ \/ _ |/ / / / / / // / _/ / __ |/ // / / ___/ __ / /_/ / /__ /___ /___/_/ |_/___ / /_/ /_/ |_\____/____/ Better? hth happy days and... starry starry nights! -- Indelibly yours, Paine Ellsworth P.S.: Thank *YOU* for reading! P.P.S.: http://yummycake.secretsgolden.com |
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