Watch the skies for the Shuttle and ISS

By Phil Plait | April 6, 2010 11:30 am

The Space Shuttle Discovery launched successfully yesterday, and it’s on its way to the International Space Station. It will dock with ISS tomorrow, April 7.

Until then, the Orbiter has to play catch up, slowly changing its orbit until it matches the station’s. The thing is, you may be able to watch this unfold! Both the Orbiter and the ISS are easily visible to the unaided eye, and in fact the station is potentially the fourth brightest object in the sky (after the Sun, Moon, and Venus). As they approach each other, you can see them as bright(ish) stars moving rapidly across the sky.

You can find out if they are visible to you by going to a site like Heavens-Above. Enter your latitude and longitude (try Google maps to get that) and it will put you on a page that gives you times, directions, and brightnesses (in magnitudes, so a more negative number is brighter) of a lot of different satellites. Click on ISS or STS-131 to get the station or Orbiter times.

All the good passes for the next week in Boulder, for example, are in the early morning. I suspect I’ll miss them. But check your local times and see if you can catch them! It’s an amazing sight. The picture here is one I took myself using nothing more than a digital camera on a tripod — click to embiggen it. It shows a time exposure of Atlantis and the ISS from 2007, and you can see how they are on very slightly different orbits. The two were separated by a small amount; you can tell by the different end points of the trails.

There aren’t many Shuttle flights left, so get out there and observe this while you can!


Comments (23)

  1. As they approach each other, you can see them as bright(ish) stars moving rapidly across the sky.

    Stars? Wouldn’t it be more correct to say objects? If we had stars in low earth orbit, I suspect we’d be in big trouble. ūüėõ

  2. Brion Emde

    I saw that this morning at 6:01 am in Loveland, CO. I was going out to the car and happened to look up at the moon and saw something very bright moving quickly across the sky from SW to NE. Later I went on the Heavens Above site and confirmed that I had seen the ISS. Apparently it was visible for almost 5 minutes. I thought that Astro Soichi-san could be taking my picture.

  3. If it is a morning pass for you, it is probably a morning pass for most of North America. 5am here tomorrow morning. Don’t know if I will make it. I have seen it many times and gotten lots of good pics. The one nice thing is that its bright enough to see without driving to a dark site (but I can get batter background).

  4. Charles Boyer

    “Rapidly across the sky” is a relative term. It takes 45 – 60 seconds for the ISS-NL to transit from horizon to horizon. is another good site finding when to look, all one need do is go to the satellite fly-by page and enter their zip code (in the US.) They also have a good iPhone app that alerts you to upcoming overflights.

  5. Trebuchet

    Charles Boyer, it can actually take up to around five minutes for horizon to horizon. Still pretty rapid movement compared to stars or planets! :)

    I love watching the ISS but have seen it with the shuttle only once. Unfortunately I live in the Great Northwet where clouds are pretty prevalent! I will nonetheless look up when passes are happening here.

    Off Topic: How come comments are locked for the asteroid occultation post?

  6. Matt T

    Meh. The picture on this post is nice. I prefer the picture a couple of posts ago of the truly stellar beauty…Kari Byron.

  7. Gee Phil, why do waste so much time on this science and space stuff. I really prefer the more controversial posts calling out fake science and disinformation. I need my daily dose of denouncing the deniers and the heated responses that follow. I can read about science and space on any NASA blog.

    OK This is my attempt at satire if you haven’t figured it out by now.

  8. the tables over at NASA HumanSpaceFlight are good quick references

  9. Well, it’ll take 3 minutes 20 seconds to pass overhead on the 11th. Too bad it’s at 5 in the morning.

    Tomorrow morning at 5:20 would probably still get 2 “dots”, but it only gets to 18 degrees above the horizon. (The morning of the 11th is 66 degrees.)

    Everything listed for the next week is early morning, from 3:43AM to 5:53AM.

    Looking at the charts, I assume that they treat 10 degrees altitude as the “visible” limit? One pass is listed as visible for only 9 seconds, with an altitude of 11 degrees.

  10. It blows my mind that not only are they not truly weightless, up there, but only weigh 10% less than here on Earth.
    Read that little fun fact in some stupid book.

  11. Waydude

    I was out camping a few weeks back, used the NASA App on my iPhone to watch the ISS transit not once but twice while we were sitting around drinking well earned Fat Tires after a day of hiking and exploring southern Utah red rock country. Last year just wandered outside and by coincidence got to see the ISS and shuttle go whizzin’ by, pretty sweet potatoes.

  12. Ben Honey
  13. Ooh, they’ll be passing just above the moon just before 6am here. Maximum altitude of 30¬į. Gonna have to look hard.

  14. Effing clouds. >:(

  15. DennyMo

    I took my then 4- and 6-year-old sons out to watch the shuttle chase the ISS a couple years ago, they were jazzed. Weather permitting, I’ll use Friday morning’s pass as motivation to get them up in the morning. (They also got excited about seeing Mercury last week, thanks for the heads-up, Phil. I know your anti-science rants are important, but I really enjoy your astronomy posts a lot more…)

  16. Rob

    There are a couple of good websites I use to find ISS sighting times. If i’m using my phone I just google “ISS Sighting” and the first page that comes up is a fairly simple text based site where you can select your state and city and get the overflight times. If I’m on my computer I go to: which tracks your position based on your IP address so those of you in China on a proxy server might get weird times!

  17. I wrote a humorous piece last year when I captured ISS grazing Ursa Major one evening. I try to do some kind of capture whenever there’s favorable apparitions. Early mornings, however, are right out for me.

  18. Sri

    Didn’t see this mentioned: Part one of NOVA’s “Hunting the Edge of Space” started on the 6th:

    Made for HD :)

  19. Caught the Shuttle going up, pre MECO, when it passed Long Island Monday. Saw the chase yesterday. Phil, you will see that the ISS has outshone Venus. I saw a “fly-by” a year or so ago, and the ISS was clearly brighter.

  20. Gus Snarp

    Saw them together this morning while walking the dog. I agree with FreeSpeaker, it was brighter than venus.

  21. My girlfriend’s little cousin caught the Discovery launch on his iPhone! –


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