Astronomy on the Slopes of Mount Tamalpais

Last Saturday night was just a few days after the new moon, a perfect time to view the stars, constellations and planets in the night sky. The darkened slopes of Mount Tamalpais offer an amazing place to take in the vast cosmos, above the city lights and closer to the stars. I attended the Mount Tam Astronomy Program, which features a lecture in the Mountain Theater, followed by viewing the night sky through telescopes set up by the San Francisco Amateur Astronomers in the Rock Spring parking lot.

A very useful handout, entitled The Evening Sky Map, was passed out to us as we walked into the Mountain Theater. It features a map of the sky showing major constellations, planets, and star clusters, as well as lists of celestial objects that can be seen with the naked eye, with binoculars or with telescopes. The map is specific to July 2012 and also has a list of celestial happenings for each day of the month. The Evening Sky Map is updated every month and can be downloaded for free here.

This month's lecture was entitled "Astrobiology Investigates Life in the Context of Space" and was given by Dr. David J. Des Marais from the NASA-Ames Research Center. He presented a number of ideas about the origins of life on Earth and how this could take place on other planets in the vast universe. Water is regarded as a critically important component to life as we know it, a solvent that can harness energy to create life. We also have to expand our minds to grasp a concept of life that is conceivably not as we know it.

The lecture was introduced by Tinka Ross from the Mount Tamalpais Interpretive Association, the nonprofit organization that has been sponsoring the Mount Tam Astronomy Program for 24 years in conjunction with Mount Tamalpais State Park. It started at 8:30 p.m. as the horizon dimmed with the pink and purple afterglow that follows the sunset. Tinka explained to us that this atmospheric phenomenon is known as “Venus’s Girdle,” a reflection of reddened light from the setting sun that sits above the dark purple of the Earth’s shadow. I’ve always thought of this as a “cotton candy sunset.”

As Dr. Des Marais talked, the twilight faded and the night sky grew darker and darker. The city lights came on in the distance, a shining distraction that mesmerized the audience as much as the fantastical images of Mars that Dr. Des Marais presented from a variety of science fiction sources. As the evening progressed, a thin layer of fog cloaked the city lights, allowing the stars above us to shine even brighter.

By the time the lecture was over, it was completely dark and the sky was bright with stars. The pathway from the Mountain Theater was lined with small lanterns, guiding the way back to Ridgecrest Boulevard. From there, it was a short walk to the Rock Spring parking lot, where the San Francisco Amateur Astronomers had set up more than a dozen telescopes for viewing various objects in the sky.

I walked from one telescope to the next, talking to the astronomers and finding out which celestial object they had in their sights. The first one I stopped at was focused on Albireo, a set of twin stars, one yellow and one blue. Both were clear and bright in the telescope, which the astronomer proudly told me he had built himself. At the next telescope, I gazed upon M4, a cluster of stars near Antares in the constellation of Scorpius. Another telescope was focused on Saturn, amazingly large and bright, its rings clearly visible. The next telescope was focused on M22, another star cluster that seemed to have thousands, if not millions, of stars. The astronomers were all patient and informative, happy to share their knowledge in a very casual environment to fans of the cosmos such as myself.

It was one of those rare nights in the Bay Area when the Milky Way can be seen, a long band of gauzy light that stretched across the sky. The familiar constellations of the Big Dipper and the Little Dipper were easy to find. The North Star shined brightly above the darkened forested ridge of Mount Tamalpais, a beacon that has guided observers for millennia. Scorpius was bright in the southern sky, easily identifiable by its long scorpion tail. Next to it was Sagittarius, which I was able to find with the help of one of the astronomers. He pointed out its Teapot component and the other stars that form the constellation. In between each telescope, I took the time to look straight up and gaze directly at the clear starry night. Far, far above us, a satellite could be seen making its steady progression across the sky.

The Mount Tam Astronomy Program is held at the Mountain Theater each year from April until October, on the Saturday night that is between the new and the first quarter moon. Parking is available at Rock Spring, a short walk from the Mountain Theater. Attendees are encouraged to dress appropriately for the ever changing weather, bring a flashlight, and carpool if possible. Admission is free of charge, donations are accepted.

The Mount Tam Astronomy Program continues through October. Here is the schedule for the upcoming months:

August 18, 8:30 p.m.
Ransom W. Stephens, Ph.D.
"The Reality Interface"
A look at how the brain processes sensory data and affects perceptions of reality.

September 22, 7:30 p.m.
Krisstina Wilmoth, NASA-Ames Research Center
"Sustainability Base"
Learn about Sustainability Base, a NASA office building that is billed as the government’s greenest building on Earth.

October 20, 7 p.m.
Dr. Chris McKay, NASA-Ames Research Center
"MSL and the search for organics on Mars"
NASA's Mars Science Laboratory will land on the red planet in August.  Find out about the mission’s rover, Curiosity, which is packed with innovative research tools designed to study the environment of Mars and contribute to the search for evidence of life on Mars.

The Mount Tamalpais Interpretive Association (MTIA) is a nonprofit organization that supports Mount Tamalpais State Park. Many of its members are active in the interpretive programs it offers on the mountain. In addition to the Astronomy Program, MTIA conducts guided hikes, staffs a Visitor Center at East Peak, and runs the Gravity Car Barn, a museum dedicated to the old railroad that used to run from Mill Valley to the top of the mountain. MTIA welcomes new members and is always looking for volunteers who want to show their love for what Alice Eastwood called "The Mountain."