I check the Spaceweather website daily - it is an interesting collection of astronomy and space news, as well as a gathering place of amateur photos of sky phenomena. This morning there was a note that the International Space Station (ISS) was making a series of evening passes for North America. After checking with another favorite site, Heavens-Above, sure enough, it was visible in a dark sky after sunset at 6:53 local time. What made it even more interesting is that the plot against a star map showed it would pass very close to the globular star cluster M-13 in Hercules.
So after sunset I set up a little mount that tracks the stars, and was ready for when the ISS made it's appearance. As I centered the faint asterism (faint from midtown Tucson) of the Keystone of Hercules, I could see the approach of the Space Station out of the corner of my eye. Nothing like a little pressure! I got the shutter open just in time, and closed it 40 seconds later, with the 70-200 zoom set to about 80mm at F/3.2. The picture was cropped slightly and color adjusted to make the orangish glow of Tucson's sodium-lit sky more neutral. The left-to-right background gradient is unfortunately real - the right side was nearer the horizon so has more light pollution... The 4 bright stars of the Keystone are nicely framed, and the bright streak is the ISS. The fuzzy patch just below the ISS streak at right is the M13 cluster, easily spotted in the field of view (about that of binoculars). An airplane also crossed the field in those 40 seconds - a busy sky tonight!
This pass was quite bright, nearly as bright as Jupiter in the southern sky, and easily visible even with the bright moon in the sky. I encourage everyone to log onto the Heavens-above site above, enter your location in the database, and look out for ISS, a lot of fun, and don't forget to wave at them as they pass over!
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