Crew Dragon and USA 245 close approach (~125 km) imaged!

From: Marco Langbroek via Seesat-l <seesat-l_at_satobs.org>
Date: Sun, 31 May 2020 11:57:54 +0200
Op 31-5-2020 om 00:56 schreef Marco Langbroek via Seesat-l:
> Op 31-5-2020 om 00:23 schreef Marco Langbroek via Seesat-l:

> On one of my images, I have it together with USA 245!
> 
> https://twitter.com/Marco_Langbroek/status/1266865368552833024?s=20
> 
> - Marco


As it turns out, I was imaging Crew Dragon and USA 245 during an actual close
approach!

DATE      UT          SSC   NAME     TARGET                   KM      angle
5/30/2020 21:18:16.99 39232 USA 245  CREW DRAGON              125.3   172.8


Now I am starting to wonder whether this was intentional, and USA 245 was
perhaps imaging the Crew Dragon?

We know that the KH-11 imaged some Space Shuttles, to inspect them for tile
damage, after the Columbia accident. We suspect they also image the X-37B
shortly after launch, to check upon them.

The analysis above is based on the 20151.85044152 elset for Crew Dragon, and the
20146.86101776 elset for USA 245.

The latter elset was 5 days old, but the position of USA 245 on my photograph is
very close to the ephemerids. Crew Dragon is about 3 seconds behind on the used
elset. So there is some leeway of a few seconds in the approach time, and hence
some leeway in the approach distance (but not more than about 25 km). But that
this indeed was a relatively close approach, is clear.

I did not know in advance, it is serendipity that I was imaging it right at that
moment, within (taking into account uncertainties) seconds of the actual close
approach.

Image was taken from 52.1420 N, 4.5016 E (Cronesteyn Park, Leiden), with a Canon
EOS 80D + SamYang 1.4/85 mm lens _at_ F2.0, 500 ISO, 0.5 second exposure, at
21:18:19 UT.

- Marco


-----
Dr Marco Langbroek  -  SatTrackCam Leiden, the Netherlands.
e-mail: sattrackcam_at_langbroek.org

Station (b)log: http://sattrackcam.blogspot.com
Twitter: _at_Marco_Langbroek
-----
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Received on Sun May 31 2020 - 04:59:06 UTC

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