Palomar Observatory (Part 2) September 11, 2013Posted by Lofty Ambitions in Science, Space Exploration.
Tags: Museums & Archives
In that post, we mentioned the twisty, curvy road up the side of the mountain. We didn’t mention the motorcyclists with death wishes, but several of the members of our tour group recounted hair-raising moments dodging two-wheelers on their way up to the observatory. We encountered the daredevils on our way down, as we took the slightly more direct path on the return home.
During our tour, one of the docent’s referred to highway S6, the twisty road that we just mentioned, used to be known as the “Highway to the Stars.” That moniker has also been applied to the big telescope at Palomar. One of our instructors at this summer’s LaunchPad workshop, astronomer Christian Ready, tweeted about our post, and in doing so, referred to Palomar as “The Cathedral of Astronomy.” Cathedrals, stars, the heavens. We are always searching for just the right language to capture and convey experience.
As soon as we entered the observatory itself, we were struck by how much the facility resembled a factory floor. In fact, we both thought of Doug’s father’s screen factory in Galesburg, Illinois. Inside Palomar Observatory, there on the ground level, gigantic steel girders hung overhead and ran floor to ceiling. The air was tinged with the smell of oil, and the floor was littered with machine parts. The industrial aura of the space was only more enhanced when our docent mentioned that the foundation for the big telescope’s mount goes down twenty-two feet into the mountaintop bedrock.
Attached to the walls—or rather, the one wall that completely encircled us—were two enormous wheels. Our docent explained that these were spare gears for the telescope’s positioning system. They’d been there from the get-go. By this point, the telescope’s operators have given up on ever needing these replacement parts. In fact, a laboratory has been constructed in front of them and would have to be demolished to get the gears off the wall. We rather like that blatant display of confidence in the big machine.
Telescope mirrors are often covered with a thin coating of aluminum. This coating needs to be replaced periodically. Just outside of the laboratory—the one blocking access to the replacement gears—is a vacuum chamber oven. Electrical coils vaporize the aluminum and deposit it more or less evenly on the mirror (there is also extensive polishing involved). This oven is used for the mirrors in the smaller telescopes at Palomar.
On the floor in front of us lay the three disassembled pieces of an 18-inch Schmidt camera that had been put into operation even before the big Hale Telescope that still operates inside the dome. This particular Schmidt allowed Caltech astronomer Fritz Zwicky to collect data that led him to put forth the concept of dark matter, as well as discover more than one hundred supernovae. This telescope was still finding new and unusual supernovae in 2011, more than 70 years after it started looking at the heavens.
In 1993, this Schmidt saw Comet Shoemaker-Levy 9. If someone hadn’t caught sight of it right about then, scientists wouldn’t have known to watch it bombard Jupiter the following May. For our readers who are also fans of the early 1990’s television show The Adventures of Brisco County, Jr., Anna is fond of saying that Shoemaker-Levy 9 is everyone’s favorite comet after Comet, The Wonder Horse. Twenty years after the celestial comet discovery, this Schmidt camera was taken apart. It will be reassembled as an artifact in the observatory’s visitor center.
When we entered the observatory’s main floor, the enormous open space that contains the 200-inch Hale Telescope, our docent ushered us to one side. After the stragglers joined the rest of the group, the docent swept his hand in a wide arc and pointed towards a tiny scale model of the Hale Telescope. He related that the model had been on loan to the Adler Planetarium in Chicago for a number of years, and that it had recently been returned to them.
They were thrilled to have it back, as it’s a motorized model that can be used to demonstrate the telescopes movement—a feat not easily seen by the public with the real telescope. After selecting a young volunteer, Sheila, from the audience, our docent informed us that Sheila would be playing the part of the night assistant. Contrary to intuition, it isn’t the astronomers who are responsible for moving and pointing the telescope; it’s the night assistant. Sheila did an admirable job of following the docent’s gentle instructions, and her efforts paid off by helping us each to understand how the telescope moves in its mount to track the night sky.
After watching the night assistant move the model telescope, we were prepped and ready for the docent to describe the Hale Telescope. Until next week, in the inimitable words of Jack Horkheimer, the late, beloved director of the Miami Space Transit Planetarium, “Keep Looking Up!” And to read the next installment on Palomar Observatory, go HERE.