Re: Sat track photo

Alan Pickup (
Thu, 23 Sep 1999 22:36:17 +0100

Raoul Behrend <> writes
>Very bad scan. But for me forget diffraction: the are no major stars on trails,
>and the trails are very too long for optical systems.
>I suggest planes. Or One plane and 2 satellites.

On the contrary, the two clearest "satellite trails" pass over the two
brightest stars in the nebula to better than 1 minute of arc and deviate
from exactly N-S by less than 1 degree (possibly much less).

To explain further, let us get the orientation correct. We need to
rotate the photo clockwise by ~110 degrees to align it with N at the
top. The left hand of the two (now) vertical lines passes over the star
Theta-2 Orionis while the right hand one passes over Theta-2 Orionis.
Though the latter is a multiple star (the Trapezium), it would measure
only 0.3 mm wide on the scale of the photo as it appears in my S&T.

The remaining trails are less sharp and distinct but E-W run at 90
degrees to the above two trails, to an accuracy of a degree or so.
Unfortunately, they appear to pass (only!) 2-4 arc minutes N of Theta-1
and Theta-2. Despite this, I agree with Rob Matson that the "satellite
crossroads" (as S&T calls it) is entirely an instrumental effect,
probably diffraction. The stellar alignments and the exact N-S and E-W
orientations are too coincidental to be otherwise.

 Alan Pickup | COSPAR 2707:  55d53m48.7s N  3d11m51.2s W   156m asl
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