Photographing The Iss

As a twist on the classic phrase, the International Space Station (ISS) is occasionally described as the only man-made thing in space that is visible from the Earth. It's only visible under certain conditions, but when it is you can just step outside, look up, and watch it pass overhead. And while you're at it, why not take a picture?

If you haven't tried photographing the stars then you should do that first. The method for photographing the ISS is essentially the same, but with a few added difficulties:

First Attempts

The International Space Station always moves from the West to the East. Exactly where in the sky it will appear or disappear will vary each time, but the sites listed in 'spotting it' above will give you a clue. Some of the available apps will point you straight to it. It could be described looking like a fast moving star, or a plane that isn't flashing, but in all honestly you should easily recognise it when you see it.

The image below shows the sort of image you can expect just from standing in your garden and taking a 1 minute exposure (assuming there's a clear sky).

blue sky with iss trail and a few stars View of ISS from garden (moderate light pollution)

If you look closely at the top-right then you will notice a kink. This wasn't a sudden change of course, it was a wobble caused by pressing the button on the camera. You can avoid this by using the count-down timer available on most cameras - you only need a couple of seconds.

close-up of iss trial with kink at beginning The result of not using the count-down timer - a nudge at the beginning

Composition

There's not doubt that there is a certain amount of satisfaction from having photographed the ISS; but if you were just pointing the camera at the sky then it won't be the most interesting picture. Once you're comfortable with the basics then you can be as creative as you want. Angling the picture so that you get some roof-tops or trees in the shot can add some interest, and make it more obvious what it's a picture of.

trees in silhouette with iss trail Including some trees to make the photograph more interesting.

Why Only Visible at Dawn and Dusk?

Both the Earth and the ISS are rotating in the same direction (CCW when viewed from the North Pole), although the ISS is rotating much faster. In order to see the ISS there are a number of criteria that need to be met (also shown roughly in the diagram below):

  1. The sky needs to be dark enough for the ISS to stand-out against the sky (e.g at the point marked "You Are Here").
  2. The ISS needs to be passing overhead, but not in the Earth's shadow, and at an angle where you can see the Sun's light reflected off of the solar panels.

When (or if) the ISS passes into this window of visibility determines how long you see it for.

Earth viewed from the North Pole, showing ISS orbit Earth viewed from the North Pole, showing ISS orbit. Earth image from http://kudzuacres.com/wwow/lessons/hydrology/earthoceanviews.html