I’ve recently had a few conversations with people who asked about my “ISS” tweets (and maybe wished they hadn’t:-). What is the ISS, and how do I know when and where to look for it? This post is a quick summary of ISS-related info – enough at least to get you started if you want to go ISS-spotting.

So, first of all, what is the ISS? Put simply it is a manned space station orbiting the earth at an altitude of between about 170 miles and 280 miles, and travels at a speed of about 17,000mph. An orbit of the earth takes just over 90 minutes. You can find much more detail in the Wikipedia entry for the ISS.

The orbit of the ISS varies over time. It isn’t visible at the same time or place every day. Sometimes it is visible in the evenings, sometimes in the mornings. Sometimes it is overhead during the day and so not visible at all. A good place to go to get a list of upcoming sightings is this nasa page. In the left-hand column, navigate to your country, region and then city. The list of future sightings for my hometown of Coventry in the UK is here.

If you are on Twitter, follow @twisst to get reminders a few hours before each visible pass. If you want to know where the ISS is now this real-time tracking site is perfect!

When you are looking up, what are you looking for? You are simply looking for a bright moving dot. It doesn’t flash, so you can’t mistake a plane for it. And it doesn’t have a tail so you can’t mistake a meteor for it. It looks like a bright star, except that it moves.

But why? The ISS is manned. That bright dot flying through the sky at 17,000mph has people on it! That’s kind of awesome. They have access to the Internet up there, and in particular to Twitter, and people tweeting about #ISS makes them feel less lonely! And they tweet from the ISS too. Follow @NASA_Astronauts for tweets from the ISS, including photos taken from 200ish miles up! Plus, quite a lot of my Twitter friends  are ISS spotters too and to know many of them are outside at the same time looking up at the same dot in the sky makes the world seem a smaller place somehow!



  1. hi

  2. nice post. thanks.

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