Really nice picture! Great framing with the bridges!
Does anyone know which direction they were going? Hmm, dumb question, I will check... Judging from
http://www.calsky.com, and it seems they both were going from roughly North to roughly SouthEast, so one the image it would mean down from top to bottom.
Also a curious thing, is it looks as if someone passed in front of the camera at least 3 times (if it was a single exposure and not around 4), because there are 3 tiny interruptions in the trails... Also interesting to note is that these interruptions (if happening at the same instant in time) show that one of either ISS or STS-130 was in front of the other one, and not both following a side-by-side route as one could imagine at first glance
![Smile :)](./images/smilies/icon_smile.gif)
In fact, calsky tells me the ISS was 2 minutes "behind" the Shuttle. So The shuttle is the trail on the left, and the ISS is the trail on the right!
![Smile :)](./images/smilies/icon_smile.gif)
(because it ends "sooner", it seems)
So we can observe the ISS is brighter most of the time, and the Shuttle is actually darker, but still peaks in brightness nicely
![Smile :)](./images/smilies/icon_smile.gif)
..
Well, being late through night, and with the info from calsky about the time of the ISS pass, I figured I'd try finding known constellations in the sky!.. And indeed I spotted Lyra to the left the the ISS trail, slightly higher in the picture than the flare from the ISS (right trail). With Lyra found, finding Hercules suddenly became a lot easier. (M13 seems to be visible in a thick faint train!) Next, Corona Borealis pops-up really nicely, but Boots is not easy to spot because Arcturus is out of the picture.
Anyway, I wanted to find a star near the celestial equator (as these leave the longest trails in the least amount of time), and I picked up Antares, the brightest star at the bottom left of the picture, at the heart of Scorpio, at Declination -4º.
The trail left by Antares has a length of 56 pixels. The angular distance between Antares and Alniyat (sigma Sco) is just over 2 degrees, and measures 81 pixels in the picture. This tells me that the resolution there is about 1.49 arc-minutes per pixel, in the vicinity of Antares, leading to Antares having a trail of 83.6 arc-minutes. Given the sky turns about 15 arc-minutes per minute, that means the total exposure took roughly 5.6 minutes (having the -4º declination into account) or just over 5 minutes and a half. Perhaps it would have been 4 exposures of 90 seconds. It is very rare to do 5-minute exposures in city skies. You would have to stop-down the aperture somewhat, and you would not be able to spot the trail left by of M13!..