The Moon and the Seven Sisters huddle up in the wee hours of tomorrow morning. The Moon will “occult” the sisters – the brightest stars of the Pleiades star cluster. The stars form a tiny dipper that marks the shoulder of Taurus, the bull.

Occultations have been useful scientific tools. The way a star vanishes, then reappears, can reveal details about both the star and the Moon.

If the star fades in steps, that probably means it’s a binary – two stars that orbit each other. The Moon covers up one star a moment before it hides the second one. Several binary systems were discovered this way. Watching an occultation at different wavelengths also reveals details about the individual stars, such as their brightness and temperature.

Occultations also have helped map the lunar surface. The Moon isn’t smooth – it’s marked by rugged impact craters, canyons, and mountains. The precise timing of the occultation reveals whether the star was blocked by one of these features.

Occultations aren’t quite as important to scientists as they once were. But they’re still interesting to watch – as the Moon “hides” a star.

This occultation will be in good view from the central and western parts of the United States, although it occurs a little late for most of the eastern part of the country. The exact timing depends on your location

Script by Damond Benningfield