The International Space Station crosses our skies on a regular basis. Many of us would love to spend time on this early starship as it circles the Earth and studies all that is above and below. But for most of us, all we can do is occasionally watch as it streaks across the sky.
But wait a minute? Why settle for a streaking glimmer like just another satellite. The ISS is actually much larger than most satellites and some of us have glimpsed it briefly in our scopes, but usually by accident. Let's go beyond accident to intentional.
The image above shows the ISS and Discovery spacecrafts. It is reproduced with kind permission from Astrophotographer Thierry Legault. Please visit his amazing website for more images.
The ISS can be photographed
People have done it and you can too. But you need to apply some common sense and a new approach to your telescopy. The International Space Station is not like the moon or other celestial objects subject to the gradual rotation of the Earth. It's moving across the sky and it’s moving fast!
Forget the motor drive
The ISS is moving too fast for most motor drives and the calculations would take you days to estimate. Besides, many motor drives simply won't move fast enough to track it. This is a handheld proposition and you can do it with a traditional reflector or better yet, a Dobsonian scope. Some people have captured a shot with a DSLR camera with a good telephoto, but they've also used some tricks. These include automatic exposures set to repeated shots and not surprisingly, video mode. In fact, the video mode is the best way to capture the ISS but you may only get a frame or two of the actual station. That's okay. That’s the idea.
The Reflector approach
To begin with, you're going to have to make everything real loose on your tripod head. You actually want your reflector to be loose in your hands so you can move it freely across all dimensions. You also want a lower magnification. You might want to experiment with magnification and here's the bad news. You usually only get one fairly fast pass a night. Figure 2 to 6 minutes tops depending on your view of the horizon. The ISS slows as it passes over your head and speeds up from horizon to horizon. This could take a few nights to capture. Once again, video mode might help. As the ISS moves into and out of your field of view as you madly track it, you'll get frames of the full station that you can isolate either on video or as a series of automatic shots. That's how most amateur astronomers have done it so far.
Dobsonian is the ticket
A Dobsonian scope gives you two advantages:
1. A wide field of view
2. A better hand-held option
The International Space-Station is moving across our skies at 17,500 mph or 28,000 kph. The Earth is also rotating at up to 1,000 mph at the equator or 1,620 kph and most likely in a different direction. We have to be nimble to capture the ISS and the Dobsonian gives us that advantage. We can cradle it and move it, although most of our tracking of the ISS is going to be a frantic appearance of the station that crosses our field of view. The video below demonstrates the technique.
The Real Challenge
Don't we all love it when we can align a planet or celestial object and track it across the sky with our motor-drives, computer programs and apps? It's so simple to share the heavens with family and friends and create first-class photos when we have a consistent and steady field of view. When it comes to the ISS... get over it. The images you capture will most likely be a bit blurred, low-res and less than picture perfect. Taking a picture of a jet flying directly over your house would be easier. And that's just the point.
The Secret to Capturing the ISS on film
Here's the bottom line.
1. You want a DSLR camera on video mode or a webcam. The appearance of the ISS is going to be fleeting across your field of view and video will give you some frame captures.
2. You need to know where and when it shows up. Here's a link to the site that tracks the ISS on a daily basis as it orbits the Earth.
3. You might want to try a Dobsonian scope with at least an 8" aperture. Dobsonians are easy to swing physically with your arms across the sky. You can do it with a reflector, but a Dob is easier. Make sure your finderscope is accurately aligned and chase the ISS over the sky keeping it in the centre of your finderscope field.
4. Use imaging software to crop and blow-up your image or using stacking software. Yes it will be blurry and not perfect, but it will be clear enough to say, "I did it."
Image by Thierry Legault of the ISS. Reproduced with kind permission
With some practice the image should become clearer and clearer. With the right equipment and skill the image above shows just what is possible. If you want to see more from Thierry and learn his astrophotography techniques then I would recommend purchasing a copy of his latest book.
You can purchase it via these links:
or via this website link
Give it a go and post your attempts below in the comments section.
Related Posts: Astrophotography
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