Monday, April 19, 2010

A Mt. Wilson Pilgrimage

This past weekend I treated myself to a science sojourn to pay a long overdue visit to the Mt. Wilson Observatory, the famed observatory here in Southern California that changed the face of astronomy early in the 20th century. This is the place with the Hooker 100-inch telescope that was, at the time, the largest aperture telescope in the world. It was there that Edwin Hubble discovered the universe was expanding. During my visit I saw some very old photos of Albert Einstein walking across the small bridge leading to the 100-inch and atop the solar tower. There was even a shot of Stephen Hawking from 1990. From a historical point of view, Mt. Wilson will always hold a very important place in the hearts of astronomers around the world.

Although I had never been up to Mt. Wilson, I decided to visit because of some exciting new science being done on the mountain with the CHARA array (Center for High Angular Resolution Astronomy) run by Georgia State University. In the April 8, 2010 issue of Nature, the CHARA science team reported new observations of a very cool eclipsing binary star system called Epsilon Aurigae some 625 parsecs (around 1,900 light years) from Earth. The system has been well known since 1821, but astronomers have struggled for decades to figure out what was causing the eclipses. The new results indicate a low-mass (2.2-3.3 solar masses) F-type star, with an opaque disk that enshrouds a single B5V-type star as the eclipsing body –some pretty exotic stuff. The CHARA array is an “interferometer” consisting of six distinct 1-meter telescopes (see inset photo) arranged in a Y configuration on Mt. Wilson. The light from each telescope is then combined with a device called a MIRC to establish a baseline 331 meters which makes it the largest optical telescope in the world.

I showed up before the 1pm scheduled time for the free guided tour and enjoyed a leisurely lunch in the Pavilion overlooking the Inland Empire far below (Mt. Wilson is at an elevation of 5,715 ft). I was promptly assaulted by hoards of small annoying flies that I later found out were a signature characteristic of springtime on Mt. Wilson. By 1pm a group of eight astronomy enthusiasts had gathered to take in the sights. The 2 hour tours are conducted by volunteer docents. Our guide was Don Nicholson, a long time Mt. Wilson supporter and son of Seth Nicholson who spent years as a Mt. Wilson astronomer specializing in solar phenomena, and also discovered four moons of Jupiter (the same number discovered by Galileo).

The afternoon was a fact-filled adventure as we walked across the mountaintop – inside the solar telescope tower, the museum, then past the 60-inch telescope, in the CHARA array visitor center, and finally up in the viewing room for the 100-inch telescope. Along the way, tour guide Nicholson added many fascinating Mt. Wilson anecdotes and was able to ably answer each of the many questions posed to him by the members of the group. His knowledge of the facility was obviously very broad indeed.

I thoroughly enjoyed my visit to Mt. Wilson and I learned a lot. I fully intend to visit again, but probably not until the road is repaired from La Canada (JPL) because the alternate route is way too long and winding, and much of the way was through a featureless burned out landscape courtesy of last year’s Station Fire. I definitely recommend a visit to Mt. Wilson as a day trip for the entire family.

1 comment:

  1. Dear Daniel; I'm headed up there this weekend on your recommendation and I'm taking my 10 year old daughter. Hope she (we) learn something!


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