It would be hard to imagine a more entertaining spectacle in the night sky than the one Marylanders can witness on the evening of July 4, if they're  paying attention - and if skies are clear.

On this one night, when lots of us are outdoors after dark anyway, we'll have the moon, the solar system's largest planet, and the biggest spacecraft anyone has ever seen - all making an appearance at the same time, and all visible with the naked eye.

Oh, and there may be fireworks, too.

Here's the deal: By about 9:30 p.m. - just about the time the fireworks are ending - the moon and Jupiter will be side-by side, low in the southwest. The moon will be at its first-quarter phase. Its right side will be illuminated by the sun, which will have set below the western horizon almost exactly an hour earlier.

Just to the moon's right (west) is the bright star Spica, in the constellation Virgo. The other (brighter) "star" to the moon's left (east) is the planet Jupiter.

But the climax of the evening will come at about 9:37 p.m., when the International Space Station will rise above the northwest horizon. It will look like a bright, steady, fast-moving star, headed toward the eastern horizon. When it first becomes visible to Marylanders, it will actually be more than 200 miles above Lake Michigan, speeding toward the southeast, passing over Lakes Huron and Erie, across New York, Pennsylvania and New Jersey, and then out over the Atlantic.

If the shuttle Discovery launches this weekend, there may actually be two spacecraft in view, including two station crewmen and seven shuttle astronauts. If they've already docked, you'll see just one point of light. But if they launch late, you may actually see two, flying one behind the other, as the shuttle chases down the station for docking. What a sight on the 4th of July! But it will all depend on the timing.

From the Baltimore area, the station will apear to fly through the bowl of the Little Dipper - just east of the Big Dipper's bowl. At about 9:40 p.m. it will reach its highest point - about 60 degrees, or two-thirds of the way up from the northeast horizon to the zenith (straight up). The station will fly on, passing close to bright Vega, a star at the apex of the Summer Triangle, before disappearing into the Earth's shadow at 9:42 p.m.

Take the kids and have a Happy Fourth! To read more, click here.