In the shadow of the northwest’s largest public access telescope, the Battle Point Astronomical Association hosts monthly star parties that gaze into Earth’s broad neighborhood.
At 7 p.m. April 14 at the Ritchie Observatory on Bainbridge Island, BPAA education manager Catherine Koehler will be delving into just what one can see out of our planet’s living room window today as she explains the Precession of the Equinox.
It took millennia for astronomers to understand the Precession — a 26,000 year cycle in which Earth’s axis wobbles, similar to the motion of one rotation of a slow spinning top.
In 10,000 years, Polaris will no longer be the North star in Earth’s sky because as the planet’s axis slowly wobbles, its view of the heavens changes. Koehler will be looking into some of the causes and effects of the oscillation.
Then later that evening, to round out the beginner’s star party, Paul Below — another of BPAA’s education managers — will be giving his presentation, “An Introduction to the Night Sky.”
“All of our beginner programs are directed at a level where you don’t have to have specialized knowledge to participate,” Koehler said. “We can answer a lot of different questions.”
For Koehler’s presentation on the Precession of the Equinox, she will have the assistance of the BPAA’s planetarium program which projects a myriad of images of the night sky on a domed ceiling inside the observatory.
“We will get to look at stars even if (the sky) is not clear,” she said. “It takes you to the north pole and then you watch … as the stars spin around you. Initially Polaris is at the north pole, but that makes a big circle and after 26,000 years its back to the same position.”
If the sky happens to be clear following Koehler’s presentation, the group will then take a look at the stars outside with the help of Below and other BPAA amateur astronomer’s telescopes.
And if forecasted sky conditions are pristine, the group may also get the chance to look through the Ritchie Telescope — which the BPAA boasts as the largest public access telescope in the northwest.