ISS Pass – March 18th

Tonight’s pass was fairly low to the horizon and not that bright (low = lots of atmosphere to look through = dimmer), but the winds had died down and while it was cool (52°F), the crescent moon was up there, so let’s give it a try! Practice, practice, practice!

Not bad! Low, almost due west, climbing at a shallow angle up and to the right, where it doesn’t even get high enough to get above that huge pine tree across the street.

Image from

As the prophecy foretold!

Shift a little to the right as the ISS clears the big pine tree, only to watch it fade into orbital night just before it gets to the Italian cypress trees. The airplane track starting just above the cypress trees and heading north (bottom center)? That’s Fedex #1839 from San Diego to Oakland, at 36,000 feet.

But wait – there’s more!

The faint line coming from center upper right to center lower left? That caught my eye just as the ISS was fading. It’s going due north to due south, so it’s got to be some sort of polar satellite. Possibly a weather satellite, or a spy satellite. Possibly ours, possibly theirs. No clue.

But I shot a much longer string of photos, continuing after the polar satellite had faded into darkness. Merging all of them you can get a great view of how stars near Polaris, the North Star, the pole star (at the lower left) don’t appear to move at all in a time lapse photograph like this (they’re dots) while stars much further away from the pole (on the right) will trail into little arcs as the Earth turns beneath them.

Still can’t find Polaris? Here’s your handy-dandy tutorial, learned lo these many decades ago on some Boy Scout camping trip. Find the Big Dipper (outlined in magenta), it’s easy, a big, bright constellation. On the far end of the dipper portion are the two “pointer” stars. Follow the direction they point (green line) about five times the distance between the two pointers, and you’ll se the one semi-decently bright star in the area – that’s Polaris!

Now go back and blow up that first picture up above. Polaris here is to the upper right of the top of the telephone pole. Again, a dot, not an arc. Now look at the stars on the far left side. See how much they appear to have moved in the two minutes of time covered by this series of pictures?

Flat Earth my ass!

(Should be another great pass tomorrow night, much higher, much brighter!)


Filed under Astronomy, Photography, Space

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