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Vixen Binocular Telescope BT80-A

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#1 xcy

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Posted 21 January 2013 - 12:35 PM

Is anyone using the Vixen Binocular Telescope BT80-A and can give some information about its performance?

#2 Mark9473

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Posted 21 January 2013 - 01:04 PM

There's some information in the archives. The focal length is rather long which is great of course for reducing aberrations, but it does limit the FOV to under 2° or so. Last year Vixen came out with a shorter BT81 which you could take in consideration. A search of this forum should turn up some useful information on both of these.

#3 CosmicEclipse

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Posted 21 January 2013 - 07:40 PM

Those have terrible CA due to the nature of their design unfortunately. When I first took a look through those, I said to myself! WHOAAA the colors man! the colors!

Pricey at that.

#4 Jay_Bird

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Posted 21 January 2013 - 08:06 PM

A convention last fall had the new 81 and little cousin 70ED Vixen angled binoculars set up indoors. I had a look through both with 20mm to 40mm eyepieces, granted not an acute test for CA, or for alignment at high power. My impression was both were nice, both bright and sharp, with the 70ED view 'grabbing' me a little more. I didn't notice any flaws or CA at those magnifications... The moon or brightest star could be a more severe test, but I was looking at brightly lit booth displays and signs about 100 feet away, with dark shadows in the view behind them.

#5 GlennLeDrew

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Posted 21 January 2013 - 08:53 PM

I looked through a BT-80 at Riverside '98. I recall its performance as being fairly decent, certainly with no false color of note at low to moderate magnification. And yes, the long-ish focal length does significantly reduce the maximum field size, which to me is something of a minus.

#6 eklf

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Posted 21 January 2013 - 09:20 PM

I have the BT-80 and find it to be a good performer. The longer functional focal length does substantially reduce abberations. The cleanliness of the view is more reminiscent of telescope than binoculars. Interchangeable 1.25" eyepieces (most but not all kinds), 45* viewing angle and 11# weight are plusses. False color on moon is surprising minor, but not so on jupiter. Saturn, however, is clean and sharp. Narrow view does take it away from typical binocular-like viewing, but I find it compliments very well my BA8 15x70s.

It is also a fine day time terrestrial scope.

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#7 charen

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Posted 21 January 2013 - 11:12 PM

CosmicEclipse
Quote:
"Those have terrible CA due to the nature of their design unfortunately"

Can you explain what you mean by that statement ?

Thanks

Chris






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