ISS Transit

October 28, 2011

Learning that the ISS would transit the sun and be visible locally, I decided to take a video camera and my digital SLR up the Mt. Lemmon highway to a turnout where the transit would be visible. I attached a Nikon D300 to my old venerable Celestron C8 equiped with a vintage mylar full aperture filter. I programmed the D300 to take a burst of shots in the hope of capturing several higher resolution transit photos. The seeing at the time was not great. The inexpensive conventional video camera did boast a 41x optical zoom and didn't require additional optics to get a full image of the sun. A piece of exposed Tri-Ex film served as the filter. All images have been enhanced to make the ISS more visible. Full transit duration is estimated at 1 second.

The short video shows how fast the ISS transits the sun. The three full-sun photos give some perspective on the size of the ISS at a slant range distance of approximately 580 km (360 miles). The last photo is a pixel for pixel image of the ISS from the second photo. The ISS subtends about 48 seconds of arc at this point.