Steve Ruhl said taking an observational astronomy class his senior year in college was a big mistake. He loved it so much, he ended up spending three more years exploring the vast world of astronomy.

Ruhl, former education director for, and the new president of, Battle Point Astronomical Association, can condense his extensive knowledge to a 5-year-old’s level, or answer even the most technical question from the association’s members. But Ruhl gives Saturday’s presentation, “Cool Constellations,” a PG-13 rating.

The free planetarium show begins at 9 p.m. Saturday at Ritchie Observatory in Battle Point Park.

Presenter Dr. David Fong, astronomy professor at Olympic College, will be sharing classic stories associated with the constellations, and some of the Greek narratives are, ahem, apparently a little racy.

Inside the dome, adirondack chairs circle a projector which beams the night sky onto a screen above. The image, similar to the concept of Google Earth, is time-stamped and can be manipulated to zoom in or to see the sky from various perspectives or times.

The room holds about 40 people, so the hour-long program begins when the first 40 people arrive. A second showing will follow, if needed. Meanwhile, and after the show, local astronomers will be on hand with telescopes outside the planetarium, since skies should be clear this weekend.

For more information, call 842-9152 or visit www.bpastro.org.