Tuesday, March 28, 2006

The Moonstick: A Moon Phase "Slide Rule"

I ran across the moonstick several years ago, and with my interest in slides rules, I was hooked. Actually the moonstick isn't exactly a slide rule, but it sure is a soul brother to slide rules.

Hexagonal in cross section, with six "slides": five of them can slide back and forth, the sixth is fixed. With the aid of the moonstick you can calculate the phase of the moon for dates up to 8000 years into the past or future. It takes leap years and all that into account.

What was the phase of the moon on the day you were born? On December 7, 1941? On July 4, 1776? On October 14, 1066? The moonstick can also be used to answer questions such as, when is the next time there will be a full moon on April 1?

Like I say, it's a soul brother to the slide rule. The moonstick is funky. You look at it and you wonder why somebody didn't invent it ages ago. It's that cool, and that ingenious.

You can get a moonstick of your own right here. Check it out!