Re: All-sky sat monitoring

From: Leo Barhorst via Seesat-l <>
Date: Sun, 8 Feb 2015 10:53:36 +0100
As Greg mentioned the system used by Cees, Scott and me can do an
all-night observation session. In spring and summer last year, when
the evening and the morning visibility window meet, I´ve done several
long observation sessions, some times lasting up to 6-7 hours. The
camera was in a fixed position aimed at the northern apex of the NOSS
orbits. For my location that is around 30 deg Az and 30 deg El. The
goal was to capture ¨lost¨ NOSS objects, but also lots of other
satellites were imaged.
At 25 fps; combining 250 frames in one 10 sec image,  you get 360
images per hour. So around 4000 in a 6-7 hour session.
Sattools, the program Cees develloped, can do the reducing of the
images while observing. I set up the system and can go to bed. In the
morning the recorded images are scanned using a viewer. As the tracks
of the satellites in the classfd.tle and catalog.txt files are
displayed on the viewed image, one can easily see a UNID.
Then only these images have to be analysed, reducing a great deal the time.

With the steerable telescope mount the camera is on, it is quite easy
to keep the camera aimed at the desired spot ahead of the earth
shadow. Also switching from the evening side of the earth shadow to
the morning side is then easy.

On the recorded images I can identify stars of around mag 7-8. Because
their light is combined over 10 sec you can see dimmer stars than
satellites, that move across the image in the 10 seconds. However
Sattools combines the imaged satellite points of all the 250 frames
into a single point at the middle of the track. In this way even
satellites just too dim to show up on the viewed images become visible
and can be measured.

I don´t have a wide angle lens at the moment. Perhaps I can do a test
run with the 50 mm lens (5x7 deg FOV) and an all-night in a few


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Received on Sun Feb 08 2015 - 03:54:20 UTC

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