I was able to observe a 34-degree elevation solar transit of the ISS from the comfort of my own front yard (a first!). Unfortunately, the usual unexpected-technical-problems resulted in no usable images. The original prediction from Thursday, based upon the Mission Control Center ephemeris, had the center line about .2 miles to the SE at 2:07:34.16 PM EST; the latest Orbital Information Group TLE (about 6 hours prior to the transit) had the center line about .5 miles to the NW, and occurring 2.66 seconds later at 2:07:36.82. At my latitude, I'm spinning around the earth's axis at about 850 mph, so 2.66 seconds corresponds to about .63 miles- roughly the shift in transit path from one prediction to the other (coming later than originally expected, I would have rotated .63 miles farther east than the original prediction, causing the track to be that much west of the original prediction- actually, the OIG track is almost exactly 1 mile west of the MCC track). The transit path width was 2.0 miles, so if the OIG prediction were correct, the transit would have been about 25% from the center of the solar disk. Since the transit lasted only 1.05 seconds... and the photos didn't work out... it's hard to tell, but I got the impression that the transit was at least twice as close as that to the center. Maybe next time... ------------------------------------------------------------------------- Subscribe/Unsubscribe info, Frequently Asked Questions, SeeSat-L archive: http://www.satobs.org/seesat/seesatindex.html
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