Starlink stream over New England (17 June 4:15 EDT)

From: Frank E Reed via Seesat-l <seesat-l_at_satobs.org>
Date: 17 Jun 2020 10:23:53 -0700
My first posts to seesat-l date back about twenty years. I haven't posted
in a few years, but this morning's Starlink stream was inspirational. 

Last night's skies over southern New England were clear, and I had some
nice opportunities for a few interesting observations from 1:00 onward. 
I was using heavens-above for predictions, and I noticed a good 
opportunity to see the latest launch stream pass over at 4:15 EDT 
(17 June 0815 UT) if I could stay awake. 

Morning twilight was underway (nautical twilight, Sun altitude near 
-9 degrees), and limiting magnitude by then was about 3.0 toward 
the south. More or less on-schedule, one satellite appeared where
expected, about halfway between Saturn and Altair heading toward 
the eastern horizon. There was only the one satellite for about 
thirty seconds, and I started to wonder if the stream had already 
dispersed. 

Then dozens and dozens of bright satellites began pouring out
from behind a tree in the southwest! Maximum altitude was near 65 deg
in the southeast. Nearly sixty satellites stretching across roughly
45 degrees in a somewhat random scatter pattern. All except one were
around magnitude 1.0 for most of the pass. The outlier, either one 
of the SpaceX experiments or maybe just debris in the stream, 
was around magnitude 3.0. Really spectacular. I have seen Starlink
streams within a few days after launch before, but this was by far
the most impressive.

The stream showed some evidence of three-dimensional structure. 
The satellites were scattered rather randomly with a few close pairs,
and as they travelled across the sky, the relative angles in a couple of
the close pairs increased. I didn't make any measurements or get any
photos, but I would guess the angular separations changed from roughly
5 minutes of arc to 7 minutes of arc (that order of magnitude) as the
satellites moved across 30 degrees of sky. I'm not sure I believe this 
was due to three-dim structure in the stream, but that was my 
strong impression.

Frank Reed
Clockwork Mapping / ReedNavigation.com
Conanicut Island USA

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Received on Wed Jun 17 2020 - 12:26:12 UTC

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