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 Facebook Visual Satellites Obs group (minor activity): https://www.facebook.com/groups/2049822665272876/ _______________________________________________ Seesat-l mailing list http://mailman.satobs.org/mailman/listinfo/seesat-lReceived on Wed Jun 17 2020 - 12:26:12 UTC
This archive was generated by hypermail 2.3.0 : Wed Jun 17 2020 - 17:26:12 UTC