Re: Starlink flaring

From: C. Bassa via Seesat-l <seesat-l_at_satobs.org>
Date: Wed, 29 May 2019 22:53:03 +0200
My observations of the same pass, and the pass later that night
confirm Marco's observations.

I've posted some pictures, a video and some graphs on this twitter
thread: https://twitter.com/cgbassa/status/1133827825113423872

The main conclusions are that the Starlink satellites flare regularly,
but vary between +6 and +4 magnitude. However, it seems they can also
reach negative magnitudes, as on the first pass some of the trailers,
which passed higher in the sky, reached magnitude -1. In video
observations of the second pass (23:21 to 23:45UTC) I was able to see
all 64 objects which have been catalogued by CSpOC, and the four
objects that they classified as debris clearly stood out in their
optical behaviour. Those four objects showed four brief flares, only
to decrease to magnitude +7 or fainter, whereas the 60 payload objects
were all either constant near magnitude +6 or flared to +4.

Furthermore, the four debris objects matched the CSpOC predictions,
whereas none of the payload objects did. This suggests that they are
actively adjusting their orbits and that all of them are, in some
form, operational.

For these observations I've been experimenting with an all sky camera,
based on an 6 megapixel ZWO ASI178MC CCD camera and a 2.5mm F/1.2 lens
(this is supplied with the camera). This lens provides a 150 degree
field-of-view (almost to the horizon). With 15s exposures I can just
make out M13 and the ~+7 mag flanking stars when they are near zenith.
This setup picks up many of the bright satellites, several of them
from classfd.tle. It is also very useful to document flaring behaviour
of many satellites. I need to play a bit with software to see if
difference imaging can pick out the satellites and if the astrometry
can be determined accurately enough for identification/position
measurements.

Regards,
    Cees
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Received on Wed May 29 2019 - 15:53:49 UTC

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