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Kowa XD44 Binoculars

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#1 asaint

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Posted 25 February 2008 - 09:26 AM

Kowa Binoculars

#2 Remy Bosio

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Posted 25 February 2008 - 11:49 AM

Allister, looks like Binoculars.com has that model but it's pricey for it's given aperature. Good review though.

#3 proud uncle

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Posted 25 February 2008 - 12:57 PM

The reviewer indicated he bought the binocular for "nature watching including Astronomy." But, the review only mentions it's performance for astronomy. Then the review recommends the 10.5x model for Astronomy, though the 10.5x was not reviewed. How does the reviewer KNOW the 10.5x performs as nicely as the 8.5? What is the aperture of the 10.5x model?

Since the 8.5x44 was reviewed, then the review would have been stronger to also discuss it's performance on more telestial nature-watching, such as birds. What is the FOV? Does actual FOV match advertised FOV? What is the minimum close focus range?

#4 Mark9473

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Posted 25 February 2008 - 02:47 PM

Shiv, thanks for your review. They are a most interesting binocular! No spikes on Sirius - says a lot not only about collimation, but perhaps even more so about the quality of the glass used and even your eyesight.

Great shot too!

#5 Mark9473

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Posted 25 February 2008 - 02:56 PM

the review recommends the 10.5x model for Astronomy, though the 10.5x was not reviewed. How does the reviewer KNOW the 10.5x performs as nicely as the 8.5?


Perhaps you have read another version of the review, than the rest of us. ;)
He said the 10.5x has a higher resolving power than the 8.5x, and would show a darker sky background and fainter objects. These are just pure facts that follow from the specs.

For some of your other questions, see http://www.kowascope.com/
But I agree with you that it'd been nice to have a longer / more detailed review of such a nice optic.

#6 proud uncle

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Posted 25 February 2008 - 05:01 PM


He said the 10.5x has a higher resolving power than the 8.5x, and would show a darker sky background and fainter objects. These are just pure facts that follow from the specs.


My understanding is resolving power and limiting magnitude are both functions of aperture. Both models have 44mm aperture. What the 10.5x does is help our eyes resolve really tight detail within the capabilities of the optics. Also, as you stated, possibly a darker background.

But, I agree, these appear to be very fine optics. Given the price, I would hope so!

#7 Mark9473

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Posted 26 February 2008 - 03:18 AM

Kenneth, you would be right by stating that maximum resolving power depends on aperture. However, binoculars are operating at magnifications very much below the optimum.

In fact, they are typically used at powers where the eye is the limiting factor for what you can see. A person with good eyesight may be able to resolve 100 arcseconds at night with the naked eye. In a 10x binocular the resolution he can achieve is then 10 arcseconds - still quite far from the theoretical resolving power of a typical binocular's objective lens.

The same goes for limiting magnitude, really. I see you have a telescope, so I'm sure you've noticed that when you swith from a low power to a slightly higher one, you get to see fainter stars.

#8 Booji

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Posted 26 February 2008 - 12:08 PM

Nice ad,

Booji

#9 Gordon Rayner

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Posted 26 February 2008 - 09:34 PM

What do roof prism spikes have to do with collimation?






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