I have been curious for a long time whether it would be possible to photograph the international space station as it passed overhead. I had been watching the NASA website and making notes of when an opportunity might come with the ISS passing in close proximity to my location. On Thursday evening 6/24/10, at 9:54pm, that opportunity came, and it was suposed to be visible for around 4 minutes, starting when it was about 800 miles away in the light of the sun, eventually passing to as close as 227 miles. Since the weather was clear, I went outside about 5 minutes prior to the beginning of the viewing window with a 500 f4 and 1.4x mounted on a 40d body. My plan was to try and hand hold the rig using autofocus and see if I could lock onto the 'dot' as it passed overhead, then find out if any detail could be captured from this far away. I made some practice shots of the moon to try guestimate the correct exposure, and I decided on 1/250, f8, iso 400, using full manual exposure, but with autofocus, and image stabilization mode 1, since it would be more of a 'hold it steady' motion than a panning motion. The ISS was easy to see with the naked eye as it apprached, and I was able to locate it in the camera viewfinder and fire off some shots while trying very hard to keep the bright dot in the center of the frame. I was surprised that the 40d actually locked focus very easily most of the time.

Of a couple dozen shots, only a few taken when the subject was the closest showed any real detail. I belive this image is my best shot. The image shown here is up-rezzed approximately 4.3 times actual size. The next image is a 100% crop showing the ISS at pixel level (actual size).

I made a second attempt to get some photos of the ISS on Sunday morning at 4:57am, with stacked teleconverters using manual focus, pre-focusing on the moon as a guide for infinity focus. Unfortunately I was unable to keep the subject in the viewfinder when it got close, and it was very frustrating. I was envisioning images twice the size and with more detail than my first attempt. Oh well, maybe better luck on a future attempt....