Watching the International Space Station (ISS)
Have you ever seen the International Space Station (ISS) flying overhead? Chances are good that you have, but if not, you can easily do so!
If you've ever looked up into the late evening or early morning sky and spotted an object that looks like Venus, Mars or a bright star that is moving quickly across the sky, but does not show the tell-tale colored and blinking lights of an aircraft, that was likely the Space Station. The ISS is a very large satellite, and being in a very low-altitude orbit, it reflects a large amount of sunlight back to Earth's surface. Even under bright city lights, it can often be sighted moving rapidly along. It's fun and easy to experience, and does not require a telescope or even binoculars.
The ISS orbits at an altitude of about 200 - 270 miles above the earth, at a speed of over 17,000 mph. The (relatively) low altitude orbit requires sighting opportunities of the Station to be fairly close to sunset or sunrise time to be visible, though the sky can still be completely dark. It's common to see the ISS literally disappear as you watch it. This occurs when it travels into the shadow of the earth.
Many other satellites can be seen, even in the middle of the night, because they are orbiting the earth at a much higher altitude that allows them to remain outside of Earth's shadow.
I have long had a little side-hobby of watching the ISS, and our beloved and cancelled Space Shuttles (which also orbited near the same altitude as the ISS, and could sometimes be spotted while moving to or from docking with the ISS). When I'm out at night (or day for that matter) I habitually scan the skies and have been out many times looking up up to see the ISS, the shuttle or other craft on orbit. It's a fascinating sight!
A couple of months ago I was out on a late evening portrait session, and looked up to see the ISS sailing along, travelling west to east. About 5 minutes later, we saw another craft following the same path, almost as bright. A little research on the internet later uncovered that the second craft was actually the European Space Agency's Automated Transfer Vehicle (ATV) on a re-supply mission to the ISS, chasing the Station down for a rendezvous.
Many other satellites can be spotted easily and often if you travel outside of town, stop and be still watching for a few minutes.
A great resource for planning sightings of orbiting craft is the free Heavens Above website. It's mostly self explanatory, and you can customize your location to have it display which vehicles you would like to see, the magnitude (brightness), direction of travel as well as exactly when and where to look. You can select from many different objects, including the Hubble Space Telescope.
Regarding "magnitude" in the displayed information you will find at Heavens Above, remember that the smaller the number, the brighter the object will be. For example, a magnitude of -2.8 will be much brighter than a 1.3 magnitude. The planet Venus can be as bright as magnitude -4.6, so that gives you some idea.
I often check the website, then plan to watch for ISS passes that will be visible at my location, set an alarm so I don't miss it, then run the family outside the house to watch when the time comes.
Many "apps" are also available for mobile devices that are wonderful tools for planning your sighting of orbital vehicles. More on those next time.
In the meantime, pause to take a look now and then even when you're in town, check Heavens Above often, and take your family out to watch when the skies are clear! It's time much better spent, than is watching "reality shows" on television!
We'd love to know your thoughts and what you've spotted. Feel free to comment here or on KFYO's Facebook page.