Monday, 7 March 2011

The ISS and Space Shuttle Discovery STS-133

Space Shuttle Discovery STS-133 undocked from the International Space Station (ISS) on Monday, and some 6 hours later made two passes visible from my locality.

The first pass was at 18:48 local time (CET) in very deep twilight, with the sun only 4 degrees under the horizon. This meant the sky was still bright blue. A crescent moon was visible (with the ISS passing only a few degrees away from it), but almost no stars.

Nevertheless both ISS and STS-133 were well visible by the naked eye around culmination: the Shuttle was about 5 to 6 degrees in front of the ISS and slightly fainter.

A second pass, this time in a dark sky, was on an extremely low elevation of 12 degrees at 19:25:30 UTC. Yet due to the very clear sky, they were well visible by the naked eye again, truely at rooftop level:

click image to enlarge

In the image, the two trails overlap at their ends, creating one long trail. A difference in brightness shows where the ISS trail ends.

The Shuttle and ISS were 7.27 seconds apart, at a distance of 2.5 degrees, with the Shuttle leading. This corresponds to 54.5 km separation in reality.

At the deep twilight passage, I used my Canon EOS 450D, laptop and "EOS Camera Movie Record" software to record a short movie (below), showing the crescent moon and the ISS passing near it, low in the west. The Shuttle was still too faint to be seen at that time, brightening to naked eye brightness only when it was closer to culmination.



Daniel Fischer said...

Capturing the earlier pass of the duo was challenging indeed - this is my best result from Germany, with long focal length and long after closest approach.

Station operator SatTrackCam Leiden said...

Nice Daniel! I'll have a new chance this evening, if current clear weather prevails. At 19:16 CET with the sun at -8 degrees I'll have a 24 degrees elevation pass.

Daniel Fischer said...

Today's pass was even more spectacular than yesterday's since the Discovery was performing a huge water dump which gave it a bright spiral tail in binoculars. The fuzzyness of its trail in this modest picture may be bearing witness to this remarkable show.

Station operator SatTrackCam Leiden said...

Hi Daniel:
I saw the "dynamic duo"again too, see the new post of today.

I missed the water dump though and its not on the photographs either: I guess the sky was still too bright here (sun at only -8 degrees).

Erwin H said...

Is saw the same as you did and captured a video of it too:

Yesterday watched again through my telescope and already thought I saw a trail behind Discovery. So it was a water dump.
BTW: I also watched ISS through my Meade ETX70 (25mm oculair) pass close to Jupiter yesterday evening I would swear I could see the solar arrays. The apparent size was about the same as the diameter of Jupiter. Do you have any luck viewing ISS through your telescope (hand guided)?