NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: ISS Collides with...
From: Peter Monta
Date: 2014 Jun 21, 13:32 -0700
That's assuming we can trust the GPS tag (actually perhaps it's a GPS/GLONASS tag, since I believe the Apple phones are multi-GNSS these days)---if the photo was taken quickly, the navigation subsystem may not have been given enough time for its best solution. But surely it's not going to report a position when it knows the uncertainty is hundreds of meters or worse.
It's an amusing joke that this image contains both a nice "optical navigation" shot and a location tag.
From: Peter Monta
Date: 2014 Jun 21, 13:32 -0700
Hi Frank,
The GPS tag in the EXIF header says 37.39xxx N, 122.07xxx W, so your estimate is out by 1.7 km or about 1 nmi. (I'm a little torn about posting the full high-resolution position, given a possible privacy concern.)That's assuming we can trust the GPS tag (actually perhaps it's a GPS/GLONASS tag, since I believe the Apple phones are multi-GNSS these days)---if the photo was taken quickly, the navigation subsystem may not have been given enough time for its best solution. But surely it's not going to report a position when it knows the uncertainty is hundreds of meters or worse.
So given previous stories from Norm that he's in the Bay Area, we can assume Pacific Time.
Yes. Looking again at the GPS tags, there's something called "GPS Time Stamp" whose value is "05:42:46.0". (But on what UTC day? Still a sliver of ambiguity there. Sigh.) Still, the extra precision is nice if we can trust it. The exposure time is 1/15 second by the way.
It would be a cool project to take a spare phone with this kind of imaging capability and set it on a roof, camped out on a semipermanent basis, taking pictures every few seconds and relaying them to a mothership. Every satellite brighter than mag 2.5 would eventually show up, along with a great many spurious signals from aircraft and the like. (This is possible, but much less convenient, with conventional cameras.)
Cheers,
Peter
Cheers,
Peter
