Why I pull up a chair at sunset

I had traveled thousands of miles for this sunset. As I sat on Waikiki Beach a few nights ago in Honolulu and watched the sun lower itself into the sea, I looked around at the many people sharing this view.

Sunset is a truly beautiful sight, but what is it that draws me and countless others to watch that fiery disk slowly sink below the horizon on any given night? After all, it happens every 24 hours. Why the fascination with something so ordinary? You've seen one sunset, you've seen them all, right?

No, of course not. Many factors can cause colorful and unpredictable variations when we bid the sun good night. Clouds, topography, and even volcanic eruptions can produce strange and spectacular effects.

I have watched a lowering sun illuminate high clouds to set the entire sky ablaze. Refraction by the atmosphere has squashed that yellow circle into an undulating red oval before my eyes. Just once, a clear sky with a view over the water rewarded me with the ephemeral green flash. And that lazy old sun, whose progress across the sky is barely noticeable during the day, reveals its motion dramatically as it approaches the horizon.

Seeing the sun move makes me feel truly a part of the clockwork of the universe. I have seen it reach out and ooze to meet the earth, and after all these years of watching, it still seems to disappear too fast. I learned long ago that it's not enough time to change the film in my camera.

That night in Hawaii, though, the sunset was different in a way that can be predicted quite precisely. A partial eclipse of the sun was occurring. What we saw lowering itself into the sea was a brilliant crescent of fire.

The moon held onto the sun as they fell together into the water. A tiny point of that crescent bade us goodbye, looking quite strange as it poked above a few scattered clouds.

I wondered how many people on that beach were aware of what was going to happen. The local paper in Honolulu had published a short article on the eclipse, but do tourists read the papers?

Perhaps word of mouth had done the job. It was fun to speculate on the reaction of someone who might look out at that sunset and be surprised by this strange sight. Like accidental observers of old, they may have even been a bit frightened.

Having left the sun and sand behind in Hawaii, I'm now back in Maryland, where another eclipse soon will be visible - if only the rain would stop. The moon, in its relentless path around us, is headed toward Earth's shadow. This time, the moon will be eclipsed.

Unlike the sun, which is hard to ignore, the moon often passes across the sky without notice. A moonrise does not announce itself by first spreading a glow across the sky. It is often a stealthy thing. But when the moon is full, it can be quite a sight, creeping through the trees or appearing suddenly over the ocean.

So Wednesday, Oct. 27, I have another astronomical rendezvous: The full moon will rise in the east at sunset and a few hours later will enter Earth's shadow. This total eclipse of the moon is the last one visible from North America until March 2007, so it's worth turning off the TV for a night.

The edge of the moon will begin darkening at about 9:14 p.m., Eastern Time, and the middle eclipse will occur at 11:04 p.m. - not too late for the kids to stay up on a school night.

The moon's disk can be colorful or quite dark during a total eclipse. It may turn blood red at times. Predictions of spooky things like this made astronomers of old quite powerful.

This eclipse is just in time for Halloween, and there's no need to pack up and travel anywhere. With the cooperation of the weather, I'm going to watch from the comfort of my own backyard.

• For information on Wednesday's eclipse, see Fred Espenak's NASA website: http://sunearth.gsfc.nasa.gov/eclipse/LEmono/TLE2004Oct28/TLE2004Oct28.html