All posts by Greg

The International Space Station 10:39 p.m. on Sunday 24th April 2011

I had watched the earlier 9:04 p.m. crossing of the ISS and this lasted nearly 5-minutes at almost the same elevation as the 10:39 p.m. crossing.  So why was the 9:04 p.m. crossing 5-minutes long and the 10:39 p.m. crossing only 3-minutes long?  The accompanying image tells the story.  At 10:39 p.m. the Sun has set further, so the ISS is illuminated for less of its course across the sky.  As you can see in the image – it barely makes Ursa Major before its lights out – fascinating!

Progress 41P and the International Space Station

Passing almost directly overhead (83 degees) on 22nd April 2011 were the automated Russian cargo vehicle Progress 41P and the International Space Station.  Progress 41P first appeared in the West at 9:48 p.m. followed just one minute later by the International Space Station (ISS).  Both disappeared from view in the ENE at an elevation of 25 degrees.  In this image both tracks are overlaid as they were both in the same orbit.  It was a fantastic sight with just a layer of thin high cloud preventing perfection (and preventing me from imaging).