BPAA puts on a good show

The Battle Point Astronomical Association has a great facility on Bainbridge Island and a dedicated and knowledgeable corps of enthusiastic volunteers. The combination adds up to a satisfying visit for stargazers both experienced and new to the hobby. I attended the association’s planetarium show and star party Saturday evening, Aug. 27, and had a marvelous time.

Helix House is home of the Battle Point Astronomical
Association, the Edwin E. Ritchie Telescope, and John H.
Rudolph Planetarium on Bainbridge Island, Washington.
Photo: Greg Scheiderer.

It all happens in Helix House, an old military radio facility in the middle of Battle Point Park on Bainbridge. The House is home to the Edwin E. Ritchie telescope and observatory, the John H. Rudolph planetarium, and association offices, a meeting room, workroom, and library.

Saturday BPAA president Steve Ruhl put on an engaging presentation about killer asteroids. Using the planetarium’s computer system, Ruhl illustrated the rapid increase in the numbers of known asteroids in our solar system, and the crazy orbits some of them take, including a great many whose orbits often cross that of Earth. He noted that a really big asteroid collision with Earth, like the one that wiped out the dinosaurs 65 million years ago, is about a 1-in-65,000,000 year event.

Oh-oh. As Ruhl understated, that would be a bad day. He showed a PG-13 video imagination of such an impact, which would envelop the surface of our planet in flame within a day. That would be most unpleasant. The hope is that, as methods for detecting and tracking asteroids get more sophisticated, we will be able to spot “the big one” with enough advance notice to be able to do something to prevent it.

A couple dozen people attended the presentation. Ruhl used the planetarium in his talk, though noted that it was a little inadequate for the topic. It’s software includes data on about 500 asteroids, a tiny fraction of the more than 30 million such objects now known.

After the planetarium show many visitors climbed the three-story spiral staircase to get a peek through the club’s showcase, the Ritchie telescope, a 27-inch Newtonian reflector club founders built themselves. On this night, the great instrument was pointed at M 13, the great globular cluster in Hercules, a favorite object at star parties. It was an eye-popping view on a perfect night. The weather was marvelously clear, New Moon was just hours away, and the site has good horizons and a fair amount of protection from Seattle’s city lights.

At least half a dozen BPAA members had their telescopes set up for viewing as well, and stargazers of all ages lined up for looks at what was up in the night sky.

For those interested in learning a bit about astronomy, you can’t lose with a visit to Battle Point. Congratulations to the club for running a marvelous outreach effort. Watch Seattle Astronomy for information on their monthly star parties.

Stalking planetary nebulae from Seattle

Despite a recent run of decent weather in Seattle, the night skies have often as not been cloudy, thus limiting opportunities for astronomical observations. Thus when the stars aligned last night with crystal clear skies, an evening without work, and a reasonably alert stargazer, I dragged the telescope out into the back yard for the first time in a while to hunt for some planetary nebulae.

The Hubble Space Telescope is a slightly more powerful instrument
than your correspondent's 8-inch Dob located in a light-polluted
 urban back yard. The Saturn Nebula didn't look quite like this
from West Seattle; there was a hint of the color but none
of the detail of the object in this Hubble image.
Photo: STSci, NASA.

The targets, NGC 6818, the Little Gem, and NGC 7009, the Saturn Nebula, were chosen because they’re in prime viewing spots in the southern sky these days, and because they’re among the remaining few objects left to be checked off as I work toward the Astronomical League‘s Urban Observing Club recognition. The clubs are a good way to organize one’s observing. The Urban Club list includes 100 objects, all reputedly visible from light-polluted skies, defined by the club as places where the Milky Way is not visible with the unaided eye. I say “reputedly” because several of the galaxies on the list have been extremely difficult to see from my back yard. But, if it was too easy, what would be the point? View all 100 and you get a nifty pin, and your name is added forever to the club membership rolls.

Last night’s nebulae were both easy to locate but tougher to see. NGC 7009 was easier, spotted very near the star Nu Aquarii in the constellation Aquarius. It appeared in the eyepiece of my 8-inch Dobsonian as a greenish-blue blob, with details such as the “rings” that earned it its nickname visible. Higher power definitely revealed more nebulosity, but washed out the color completely. The Little Gem was a bit tougher, just to the west of a “peace sign” asterism in Sagittarius. A couple of magnitudes dimmer than the Saturn Nebula, NCG 6818 revealed just the slightest hint of color. The moon was not helpful with these objects, as it was just a few days past full and low in the east during the pre-midnight hours during which I was observing.

I visited a few old friends during the evening, including the double cluster and the Ring Nebula, before calling it a night a little before 1 a.m.