Depending on the observer's location, the ISS can then easily be seen up to four times per night. In relation to other satellites in near-Earth orbit, it is much larger and hence reflects much more light. The solar panels alone span 73 metres, while the main station is 52 metres long and 27 meters high, making the ISS the largest man-made object in space. It's also only km up. Normally, it is easy to spot the ISS with the naked eye, and it is the brightest object to be seen after the Moon and Venus.
The ISS circles the Earth in an elliptical orbit at a speed of 28 km per hour, and takes about 90 minutes to make one orbit. A ground observer can usually only see it briefly as it speeds overhead, appearing as a very bright, fast-moving point of light. Further, for a ground-based observer to see it at all, two conditions must be met. First, the observer's location must be sufficiently dark, and, second, the ISS must be illuminated by the Sun. Therefore, for an observer located on the night side of the Earth, seeing the ISS is usually only possible for a brief time just after sunset or just before sunrise.
Think about an interesting foreground for the image. A fully clear night is ideal, but you can still attempt an ISS photograph with light or patchy clouds. In fact the bright light passing in and out of areas of cloud can create an interesting image, as seen above.
PhotoHound is a website for photographers to share information on attractive photo spots, how to get there and in what conditions including astrophotography. If you have a particular location in mind, find it on Instagram and look at the most recent images. Google Maps has great coverage on Street View which may allow you to visually compose your shot and do location scouting without leaving the house.
Arrive at your location early and take plenty of test shots to ensure your composition will work. There are two reasons to avoid this approach. Firstly, a capture of several minutes will almost certainly be overexposed. Secondly, if there are any stars in your image these too will start to create a light trail.
When you create your test shots, check your stars to ensure that they remain as sharp points of light. Above you can see a comparison - on the left is an image taken with second exposure, where the stars are trailing and overexposed, and on the right is an image taken with a 10 second exposure, that has crisp, sharp stars.
Though there is no hard and fast rule on settings, here are some pointers to find a setting that works for you. Adobe Photoshop makes this easy. Below is our step-by-step guide for the Photoshop method. Select all the layers and set the blend mode to lighten. Side note: If there were stars in your image, these too will have started to trail. Duplicate one of the layers and save as a new layer. Select the rest of the layers and group these to a new folder.
Add a layer mask to the folder. Click on this mask. Then grab a black brush and paint onto the ISS trail. The ISS trail will be removed as you do this. Finally, invert the mask. Now, only the ISS trail will now be overlaid onto your base image. You can of course continue to edit it in Photoshop, or save it to process further using other image editors such as Lightroom or Luminar. The International Space Station is a spectacular and dependable subject to photograph.
Armed with these tips, clear skies and a little patience you can create images with a real wow factor.
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