Image: Sky & Telescope

Most of us in North and South America are out of luck for tonight's heavenly showthe first total lunar eclipse of the 21st century. But residents of Europe, Africa and Asia should easily see the spectacle (if they're awake at the right time), and a few fortunate people in Alaska, New England, Quebec and Canada's Maritime Provinces may also get a glimpse.

The whole affair begins at around 18:42 Greenwich Mean Time, or Universal Time (UT), when the moon starts to slide into the shadow, or umbra, that Earth casts away from the sun (see illustration). That shadow will slowly crawl over the moon's face until the satellite becomes fully covered at 19:50 UT. The moon will stay completely shaded for about an hour, during which time it will probably remain visible to the naked eye, although it will seem much dimmer than normal. Sunlight filtered and bent around Earth's atmosphere may bathe the eclipsed moon in a reddish-orange glow. At approximately 20:52 UT, the moon will slowly peek round the other side of Earth into the light once again.

If you do live in the Western Hemisphere, you need not miss the moon's disappearing act: tune into a webcast of the event from Japan at 18:00 UT. Also, you should easily be able to see two total lunar eclipses that will take place on May 16th and November 9th in 2003.