Determination and careful planning will sometimes pay off.
I’m sure just about everyone knows what the International Space Station is. The huge satellite is even quite visible from earth. Shining like a bright star, it glides silently overhead. You can see it, if you know when and where to look. Every once in a while, it’s trajectory takes it right in front of the moon… visible from certain minute strips of earth’s surface. Usually, you must be willing to move around a bit to see one.
That is what I did. Using the fantastic online calculator calsky.com, I noted that a lunar transit was going to occur within 20 miles of my house on February 7th. A quick glance at an extended forecast proved promising weather. Such an opportunity! I immediately applied myself to the challenges. A location on the transit centerline must be found. Not only that, I had to find a place where I could safely setup for the 1:30 AM transit. I chose a place with a large, empty parking lot.
Night before the transit: I and my dad (I want to thank my dad for coming along, being there and helping… thanks Dad!) caught snatches of sleep as we waited for our agreed time of departure. All my equipment was safely and carefully stowed in the car. I mentally went over and over a checklist, thinking of every possible thing I would need. OTA, check. Mount and accessories, check. Battery box, check. Printouts of time, lunar locations, etc. Check. Laptop and hard drive, check. New ASI120mc astronomy camera, check. We drove away, right on time. I set up at our location, and was pleased that I had forgotten nothing!
7 kilometer-wide line of visibility. 56 arc-second angular diameter satellite. 0.087 by 0.117 degree camera telescopic field-of-view. A 0.67 second long transit.
The minutes ticked down to the transit. I checked, double checked, triple checked my lunar location to the predicted path. Seconds flew by in a hurry, counting down to the transit at 1:30:39.51 AM. I checked the focus again. Then I glanced at the computer’s clock. 1:29! I frantically started the capture. The time that seemed to fly seconds before now slowed itself to a dragging crawl. A full eternity of 30 seconds elapsed while my dad and I stared intently at the screen of my computer. The clock hit 1:30. I stood up from my hunched position with a sinking feeling and a sigh. “We missed it,” I remarked aloud. I had prepared myself beforehand for this. I knew there was a huge probability that something would go wrong, and that I wouldn’t get it. I stopped the capture, and immediately went to the capture folder.
I opened the video. Neither my dad or I saw anything during the capture, but we both wanted to see it. 1, 2, 3, seconds in, and just wavering lunar craters. 4 seconds… 5… 6… 7… “There it is!” I said when an unmistakable black blot flicked across the frames. Against all the odds, I had captured the ISS on 3 frames.
Processing all the data to get this image was also quite a challenge, but I won’t bore y’all with it. Enjoy the photo.