Our skies will be clearing off by Tuesday evening - just in time for Marylanders to get a fine view of the International Space Station as it flies high over Baltimore. The flyby begins at 7:39 p.m. EDT, only about two hours after the shuttle Discovery is scheduled to pull up alongside the ISS and dock.

UPDATE: Tuesday 5 p.m. Here's a picture of the pair just before they docked, snapped from Holland.

The Discovery crew of seven includes Maryland native and former Waldorf science teacher Richard Arnold (right). There are three crew members aboard the ISS, for a total of 10 humans zipping up the Eastern seaboard, passing 220 miles over Baltimore at a speed of 17,500 mph. Imagine Arnold's two daughters looking up and seeing Dad soaring over like a star!

Look for the ISS and Discovery to appear above the southwest horizon at 7:39 p.m., like a bright, moving star, rivaling Venus in its brilliance. It will be barely 25 minutes after sunset in Baltimore, so the sky will still be quite bright. But observers should have little difficulty spotting the station, which will be reflecting the light from the just-set sun.

From there it will fly very close to the bright star Aldebaran, the reddish "eye" of Taurus the Bull, which may or may not be visible in the dusk. It will move close (86 degrees) to the zenith - (90 degrees) straight up - at 7:42 p.m.

Then it's off toward the northeast, passing just beneath the bowl of the Big Dipper before disappearing at 7:46 p.m. Those stars may not be visible, either, depending on where you are.

With luck, Discovery will be slow, and late in pulling up beside the ISS. That would give us an opportunity to see the two objects as separate dots of light - one brighter (ISS), the other dimmer (Discovery). I've seen that twice, and it's quite a spectacle.