re: Starlink Trains seem to have been darkened, as Space-X promised

From: Richard Cole via Seesat-l <seesat-l_at_satobs.org>
Date: Fri, 15 May 2020 12:54:50 +0000
Typo - L1.2 train corrected to L1.3.

...

At the end of April SpaceX stated:

   Making the satellites generally invisible to the naked eye within a
   week of launch. We're doing this by changing the way the satellites
   fly to their operational altitude, so that they fly with the satellite
   knife-edge to the Sun. We are working on implementing this as soon as
   possible for all satellites since it is a software change
   https://www.spacex.com/news/2020/04/28/starlink-update

That change has been implemented, at least for two trains at 380km. Last 
night (14th May 21:40UT) the L1.3 train was dark passing south of UK. 
The previous roll-angle mode would have presented the full face of the 
sunlit panel to me, but nothing was seen of the complete train 
(naked-eye). This morning (15th May 01:30UT) the L1.4 train was 
observed, again to the south, this time with binoculars. The full face 
of the sunlit panel should have been visible, but all objects apart from 
one were magnitude ~4.5.

So apart from the first week of each mission (as stated in the quote) 
the days of bright Starlink trains are over, as SpaceX promised.

If the panel was edge on to the Sun, I was seeing the panels at glancing 
angles of 26 and 13 degrees in the two cases, respectively, but the 
panel surface is dark and sunlight reflection is from the edge of the panel.

The one exception on the L1.4 train was SL-1235 which was the first 
magnitude object that would have been expected with the previous 
roll-control mode.

I did not seek to observe Starlinks that are under power on the way up 
to 550km to see if they were using the same knife-edge mode.

regards

Richard Cole

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Received on Fri May 15 2020 - 07:55:32 UTC

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