(meteorobs) Geminids from Greece -Addendum to J.D. et.al.
stange
stange34 at sbcglobal.net
Mon Dec 15 14:12:24 EST 2008
The nice thing about a Zoom lens is that you can kinda guess at the height
and use the Zoom feature to adjust a full circle of vision in an image. The
bad part is it adds more glass into the system which effects transparency
and astigmatism, internal lens reflections, and sperical distortion.
With a fixed focal length lens you must accurately determine the height
before mounting or plan on adjusting the mirror height to obtain that full
circle to compensate for height error. (Which is what I did on my 8.5mm
fixed lens for the IR experimnent).
Anyway, for clarity to anyone else just starting out.
YCSentinel
(with +200 lbs of computers running every night to level the home
foundation)
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