Here’s a nice sequence of exposures showing the International Space Station passing in front of the moon.  As seen from Los Angeles, 21.16 hrs on 23/06/10.

There’s no fixed interval between frames – just as fast as I could click, which is about 1 per second. Canon 30D 100-400 L zoom at 100mm. 0.6 seconds, f 7.1. 800 ASA.

Here’s an enhanced pic, just to bring out the stars in Scorpio, including red supergiant Antares at lower left.  M4 and M80 are invisible in the flare there somewhere.