Re: Catching the satellites on video

From: C. Bassa via Seesat-l <seesat-l_at_satobs.org>
Date: Wed, 8 Apr 2015 22:50:50 +0200
Hi Vlad,

On Tue, Apr 7, 2015 at 11:34 PM, Vladislav Gooba via Seesat-l
<seesat-l_at_satobs.org> wrote:
> Hi all. Last time I'm very interested in filming the satellites. But there's no
> information about this in the Internet.
> What setup is needed for it? What affects in
>  main parameters such as quality, limiting magnitude, fov?

Quite a few of use use video cameras for satellite observing,
primarily to obtain positional measurements to keep our orbits
updated. The majority of us use similar equipment; a low-luminosity
video camera from Watec or MINTRON and a cheap but fast 50mm (F/1.8 or
even better F/1.4). These cameras are analog, but cheap adapters are
available to digitize the signals. The 50mm lens will give you a field
of view of about 7 by 5 degrees, and reaches down to about magnitude 8
with a Watec camera and a F/1.8 lens in a single frame from a
reasonable site. To obtain accurate timing you can either use a GPS
time inserter which stamps each individual video frame with the GPS
time, or you can timestamp invidual frames as they are received by the
computer from the computer clock, provided that is synchronized. For
the reduction you can use Ted Molczan's ObsReduce.

For the setup I use I have written my own software to acquire and
analyse video observations. This is open source software that runs on
Linux (see https://github.com/cbassa/sattools). It timestamps the
individual frames from the computer clock and then uses sets of 250
frames (equal to 10 seconds of data at a 25Hz frame rate) and a
special compression scheme to generate a file (four-frame) every 10
seconds which contains the required information to accurately measure
the position and time of the satellite. The software has commands to
help calibrate the astrometry of the individual four-frames, overlay
satellite predictions and measure positions. The software is also able
to send commands to computer controlled mounts to slew the video
camera to specific points on the sky to catch specific satellites. The
mean reason why I wrote this software was to make measuring satellite
positions from video observations as easy as I could, and I think this
succeeded quite well.

Let me know if you are interested and I'll happily provide more information.

Kind regards,
    Cees
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Received on Wed Apr 08 2015 - 15:51:35 UTC

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