Friday, April 5, 2013

ISS: Double Pass This Weekend

Finally the weather is improving and time to get outside and enjoy spring.  This weekend offers the opportunity to see the International Space Station (ISS) pass over the area twice.  Both passes will be excellent and highly visible without the aid of binoculars.

ISS streaks across the sky.  Image Credit: Andreas Möller.

The first opportunity to see ISS will be Saturday evening.  If you have an unobstructed view of the southwest horizon, you will be able to see it rise immediately beginning at 9:27 p.m.  Most will be able to see ISS by 9:30 p.m. in the southwest moving toward the northeast.  About a minute later it will pass through the constellation Orion.  You might want to try taking a time exposed picture.  It will reach its maximum altitude at 9:32:52 p.m. about two-thirds above the northwest horizon.  However, just 17 seconds later it will move into the earth’s shadow and disappear.  If you are in a dark environment, this can be quite interesting to watch.

The ISS track for Saturday, April 6, 2013.  Times are local and on a 24 hour clock.  Click on the image for a larger view.  The dash line is the track in the earth's shadow.  Image Credit:

The weather should cooperate, but there may be some high, thin clouds moving in from the west.  You should be able to see it even if they arrive a little early.

If you miss the passage on Saturday, there will be an even better one on Sunday.  This will occur a little earlier in the evening beginning at 8:38 p.m. in the southwest sky.  The space station will be moving northeast and will pass very close to the bright star Sirius, in the constellation Canis Major, at 8:41:20 p.m.  This will be a good time to have binoculars to view the pass.  The maximum altitude and brightness will occur at 8:42:35 p.m. about two-thirds above the southeast horizon.  You should be able to follow it all the way to the northeast horizon.  This passage will last about 9 minutes from horizon to horizon.

The ISS track for Sunday, April 7, 2013.  Times are local and on a 24 hour clock.  Click on the image for a larger view.  Image Credit:

Weather should be great for this passage.  Clouds are not expected to be an issue and the temperatures will be warmer.

Note:  The threat of freezes appears to be over and even the frost danger is very low.  This promises to be a great weekend for planting that garden.