international_space_stationThis week I want to talk about something very man-made.  It doesn’t necessarily fit the “Wilderness” theme, but it most certainly fits in with “Exploration” and “Adventure”, and it’s just cool.  The International Space Station is a wonder of engineering and human accomplishment.  Since the first component launched in 1998, it has grown to over 450 tons, 110m long, and is the largest, brightest man-made object in orbit.  The station is very reflective, and appears as bright as Venus during a typical flyover.
This week, viewers in the Mid-Atlantic will have two excellent chances (weather permitting) to view the station as it passes overhead.  (Viewers in other areas, check the links at the bottom of this post for info on when it’s visible to you).
The Space Station is FAST, about 17,200 mph (27,600 kph) at an altitude of about 250 miles (402 km), and orbits Earth once every hour and a half or so – it completes 15.5 Earth orbits every day.  So why don’t we see it all the time?
For one thing, the ISS’s orbit is tilted 52 degrees or so from the equator.  This allows the station to pass over both northern and southern hemispheres, and as the Earth rotates underneath it, its path over the ground appears as a sine wave that slides east to west with each orbit.  As a result, only a few orbits will pass overhead any given location in a day – but it gives inhabitants of the station viewing access to 95% of the planet before the pattern repeats.
Second, you need just the right combination of conditions for the station to be easily visible to the naked eye:
1) It must be dark at the viewing site.
2) The station itself must be in sunlight.
Effectively, your best chances are soon after sunset, or shortly before dawn, where the sun can reflect off the station 250 miles up, and make it light up in an otherwise dark sky.  Most times, you can actually watch the station either emerge from, or plunge into, Earth’s shadow, and see it go from extremely bright to…just GONE… very quickly.
The nature of the orbit tends to generate “clusters” of viewing opportunities, and this week there are excellent ones on Monday 1/16, and Tuesday 1/17.  Unfortunately, if you’re not an early riser, they’re both pre-dawn – but I know many people following my posts have kids at the bus stop long before the sun comes up, and this will add some spice to the morning.  (At least on Tuesday…enjoy the MLK Day holiday!)
Monday, 1/16 –
In the Mid-Atlantic…  Just prior to 7am, the station should rise in the northwest, arc really high, passing just south of the zenith and set in the southeast. Will be visible from horizon-to-horizon, and take about 6 minutes, 20 seconds (6:20), to transit the whole sky, shining brighter than Venus the whole way.
Tuesday, 1/17 –
Just after 6am, look for it to wink into existence about 30 degrees above the horizon in the northwest, as it passes out of Earth’s shadow and into the dawn.  Again, it will pass almost straight up and set in the southeast, visible all the way to the horizon, and again very bright.  Transit time is a little less than 5 minutes.
For precise timing based on your specific location, there’s an excellent website here that will allow you to enter your own location and see appropriate viewing maps for all the passes – even the less-than-great ones.
As you watch, think about what you’re looking at – a 450-ton object built piece-by-piece, assembled in orbit, by people, over the course of almost 20 years, and currently home to 6 brave people doing some amazing research for mankind (
Peggy Whitson, USA, Flight Engineer
Oleg Novitskiy, Russia, Flight Engineer
Thomas Pesquet, France, Flight Engineer
Andrei Borisenko, Russia, Flight Engineer
Sergei Ryzhikov, Russia, Flight Engineer
Shane Kimbrough, USA, Commander
You can almost imagine them waving back at you…
I’d love to hear from everybody – I’ll keep my fingers crossed for good weather, and I’d appreciate hearing whether or not you manage to get a glimpse!
Get out there!

One thought on “Astronomy: Week of 1/15/17 (International Space Station)

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s