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Teo

13 Ian 2013 17:32



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Un review frumos realizat al unei lunete acromate cu apertura 150 mm, si un raport focal  f/5.9.

http://www.skynews.ca/PDFs/BigGlass_6inch-refractor.pdf


Iata cat de frumos incepe povestirea acestui astronom pasionat de refractoare :

" My affection for refractors goes back more than
50 years, when I used earnings from a
summer job in 1960 to purchase a 3-inch
Unitron equatorial refractor. Converting
what I paid for it then into today&#8217;s dollars,
it cost me $2,800!...."
.............................................

"Now, some would ask, why a big refractorat all?
Why not an 8-inch Newtonian
Dobsonian? Or an 8-inch Schmidt-
Cassegrain? Given the limited space I
have here, I will outline what I regard as
the most important points.
Achromatic refractors produce the
steadiest visual images of any type of telescope. "
..............................................

" In testing this telescope, I have to say
I was surprised by the sharpness of the
optics. In fact, this is the best f/6-class
achromatic refractor I have ever looked
through. At 240x on the night of best
seeing, stars produced textbook-perfect
images. The Hercules Cluster (M13) at
150x was a glorious mass of stellar points.
At 180x in good seeing, Saturn was sharp
and contrasty. Furthermore, the blue/
violet fringing was barely noticeable.
However, as expected, on the Moon&#8217;s
limb, it was quite evident.
In comparing Saturn with the view in
my Astro-Physics 155mm apo refractor,
the ringed planet had a pale creamy hue
in the apo and appeared yellowish in
the achromat. This is because the blue
is being subtracted from Saturn&#8217;s light
by chromatic aberration. However, in
comparing the 6-inch achromat with a
5-inch apochromat, the test was close on
Saturn,with slightly more detail revealed
by the achromatic scope. "

Restul puteti citi aici :

http://www.skynews.ca/PDFs/BigGlass_6inch-refractor.pdf

Va urez lectura placuta !

