Re: Video camera for scope

From: Björn Gimle (
Date: Sun Jan 18 2004 - 10:45:55 EST

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    Thanks, Kevin
    indeed this seems to qualify the PC164C for observing most satellites,
    except high-flying non-flashers.
    If the pixel density is somewhere near 480/10 mm, a satellite traversing a
    pixel moves 1/9600 radian with a 50 mm lens. In 1/60 second a LEO moves 1/8
    km, so with traverse motion at less than 1200 km range it would spend less
    than this time on each pixel, and the mag limit would be degraded
    accordingly. At longer range, an integrating camera (or longer exposures)
    would be beneficial.
    Yesterday I saw #22519 USA 89 PKM, predicted at +8.5 at 4800 km range - that
    was easy in my 810 mm f.l. f/4. At prime focus, a video camera will have too
    small FOV ( 1 mm = 4' ). I am curious how a webcam would do through the
    The review in Sky & Telescope that I referred to was in Feb.2003. The lux
    rating of the StellaCam-EX, priced at 5x the PC 164C, is 0.005 - 16 times
    (3.5 magnitudes) inferior to this - in non-integrating mode!
    Yet they claimed 12th magnitude with a 85 mm f/1.4, but only 10th mag with
    an 11 inch f/3.3 for PC 164C ! And you get 9th with a 2 inch. I don't see
    how these numbers can be compared.
    Since then, Orion also advertizes an "Electronic eyepiece" like Meade's, and
    they have their LPI (Lunar and Planetary Imager) - which tell very little of
    their sensitivity (no lux rating given for the review of the Mead eyepiece
    ----- Original Message ----- >
    > > > The video camera I use is rated at 0.0003 lux. Using that 50 mm F1.4
    > > I can see stars down to
    > > > around mag 9. Since the camera is sensitive to different frequencies
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