Monday, April 14, 2008

ISS Flyover - Monday 4/14

Many thanks to Tom for this info:

On Monday, April 14, there will be an
excellent pass of the
International Space Station over Phoenix.
The ISS reaches will appear low in the
northwest at 7:33 p.m., and pass nearly
through the zenith. It will
disappear into the earth's shadow at 7:38,
when it will be low in the

Since the moon is in the sky, it was worth
checking the CalSky Web site
( to see where the
Space Station could be seen
to pass in front of the moon. Since the
ISS is only 300 miles away
when it's near the moon, parallax is significant;
the path width is only 3
miles. Go outside that path, and you see only
a near miss. It's best
to be on the centerline.

I plotted the centerline over the Valley, and
uploaded three images to
my Web site.

The first image is obviously an overview. Scroll
down to the next two
to find better detail that will put you on the
centerline. Note that
since the ISS travels at 1 degree per second,
it takes only a half
second to cross the moon's disc.

Provided you're willing to travel, events that
involve a silhouetted
ISS in front of the moon or sun are common.
But this event is rare in
that the ISS will be illuminated brightly
during the transit. Its
surface brightness will likely be quite a
bit higher than the sun.

How do I know that CalSky works? I used it
this past Tuesday to
produce this image of the ISS transiting
the sun.


Terri, Events Coordinator
Phoenix Astronomical Society