RE: Sat track photo

Tobias, Lynn (Lynn.Tobias@West.Boeing.com)
Fri, 24 Sep 1999 16:02:12 -0700

According to the accompanying text, the satellite crossed the field in
approximately one second.  I counted about 46 oscillations in the track,
making the frequency suspiciously close to 50Hz.
The amplitude looks greater than the elongation of the star images.
Could this be related to how the CCD elements are sampled and "flushed",
aggravated by rapid motion of the image across the elements?  The
oscillation appears to be more of a horizontal/vertical zigzag than a smooth
sinusoid.
Lynn

> ----------
> From: 	Allen Thomson[SMTP:thomsona@flash.net]
> 
> Bruno Tilgner enquired:
> 
> > As we are on the subject of unexplained pictures, please have a look
> > at http://aida.astroinfo.org/sposetti/Cosmos1275r.jpg. In this case
> > it is at least certain that the trail was produced by COSMOS 1275 r.
> > But what caused the sine wave pattern ?
> 
> It looks as if it's a periodic error in the telescope's drive. Notice that
> some of the star images are elongated in the direction perpendicular to
> the
> satellite track.   Further study could back out the temporal period of the
> oscillation and see if it corresponds to anything in the telescope's drive
> mechanism.
> 
>