NavList:

Hi Peter,

Nice ISS photo! You wrote: "Question: where am I?"

You are at the center of the universe: Silicon Valley.

The time is always the largest uncertainty in this sort of fix, both because your camera's clock (or whatever you used to time the photo) and the satellite's mean longitude could be in error by a second or two. In theory, a single satellite at an instant of time would determine a fix. In practice, you get a range of possible positions at slightly different times. So rather than give a single position, I'll give an LOP: you're somewhere along a line that runs through Stanford University and right along the axis of Silicon Valley, paralleling the highways. Assuming the time is correct within a couple of seconds and the ISS orbital longitude isn't too far out, you're along an LOP running between 37.54°N, 122.34°W and 37.35°N, 122.08°W. Picking a middle point, I'll go with 37.43°N, 122.19°W (which is about a mile northeast of SLAC, the Stanford Linear Accelerator, for anyone who wants to go looking for this location).

After I had the general area narrowed down to somewhere south of SF, I noticed that the ISS path across the sky in the photo seemed too steep. It should be climbing from lower left to upper right in your image but at a shallower angle. Then I realized that this motion is the composite of the actual motion and the motion of your camera during the exposure. In order for the path to be steeper, that means that we can identify the start and end points of the star trails. They start towards the lower right.

URL from heavens-above.com for the ISS at the time of this photo and from my best position estimate:
http://www.heavens-above.com/passdetails.aspx?lat=37.43&lng=-122.19&loc=PeterMonta&alt=0&tz=PST&satid=25544&mjd=56527.1731259954&type=A

By the way, a digital camera/space station/Internet determination of an observer's position independent of GPS calls for a press release, wouldn't you say?

-FER

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