Friday, January 27, 2006

August 3, 2000

With no planetary diversions of evening viewing, this is an ideal month to observe the galaxy in which we live. The Milky Way spans the sky from east of north to west of south, passing overhead by midnight.

It seems that most urban dwellers have never seen this spectacle, which is a tragedy. There it is, right above our heads: one of nature's wonders. Yet even when the sky is clear of clouds and moonlight, pollution from artificial illumination wipes out the night just as surely as sunlight.

So you will have to travel into the countryside to spy the dark sky; but then all you will need is your naked eye.

What you will notice is a nebulous and patchy pale white swath. What you are actually seeing, as Galileo was the first to glimpse through a telescope, is a collection of countless stars.

The reason the stars are so bunched together along this band is that our galaxy is flattened like a disk. Thus, when we look along the plane of the disk we see the most stars. The individual stars we see in the rest of the sky are fewer and closer because they only populate the relatively thin width of the disk in our vicinity.

In fact, if you face the Teapot asterism -- low in the south after dusk -- you are peering into the center of the galactic disk, its densest part.

Locate the Teapot on the 10th: slightly tilted, handle on the left, spout on the right, lid directly below the Moon. Then head out into the country two weeks later, after the Moon has vacated the premises, leaving the Milky Way's glow unrivaled.