Mauna Kea Observatory

When I entered the Caltech astronomy department as a graduate student in 1985, I had a strong interest in stellar astronomy and little interest in cosmology. I also was fairly sure that I wanted to get involved in computer modelling. Neither of these interests has changed much down the years.

One problem was that, while there were some good observational stellar astronomers in the department, the theoretical emphasis was almost entirely on cosmology and general relativity. Computer modelling was considered a branch of theory at the time, so I had put myself in a difficult position. (Objectively, I should perhaps have chosen to attend Princeton or the University of Chicago, but I had strong personal reasons for preferring Caltech.) To make matters worse, most of the stellar astronomers in the group were already saturated with graduate students, so finding an advisor was beginning to look like a problem.

The resolution came when Ann Merchant Boesgaard from the University of Hawaii received a Guggenheim Fellowship that allowed her to become a visiting professor at Caltech. An arrangement was worked out whereby Ann would split advising duties with Ken Libbrecht, a solar astronomer at Caltech who had some interest in branching into stellar astronomy. Ken was a helioseismologist who had run lengthy experiments to measure the slight vibrations in the Sun's surface. These give clues to its interior properties.

One of the fringe benefits of having Ann as an advisor was that I got to go to Hawaii, not once, but twice as a graduate student. The first visit was for just under two weeks, and most of it was spent at Mauna Kea Observatory. The second visit was for over a month, during which I did the bulk of the analysis for my dissertation. No, really. I'm geek enough to have actually spent much of a month in Hawaii working. Besides, graduate students live in a whole 'nother world. This is not to say that I did not have loads of fun, including the time I sang Bach cantatas while riding through the fringes of a tropical storm on a moped. But that's a story for another time. I want to talk about Mauna Kea.

Every observatory has its own character, and my impression of Mauna Kea was that it was very modern and drew a highly cosmopolitan set of observers. Unlike Palomar, which is almost exclusively a Caltech operation, there are so many players in the funding pool at Mauna Kea that astronomers come from all over. At the time I did my observing run with Ann, the Keck Telescope was still under construction, and we worked at the Canada-France-Hawaii telescope, a respectable 140" instrument that was the largest optical telescope on the mountain at the time. We were trying to look at an elusive beryllium line in the near ultraviolet spectra of stars slightly hotter than the sun, to see if a peculiar deficiency of lithium was mirrored by other light elements.

Working at a telescope on the tallest mountain in Hawaii sounds like loads of fun. It mostly is, but watch out for altitude sickness. The road to the telescope passes between Mauna Kea and Mauna Loa before heading up Mauna Kea, and it crosses several relatively fresh lava flows from Mauna Loa. You aren't supposed to take rental cars on the road. This road ends at Hale Pohaku, Mauna Kea's equivalent of The Monastery at Palomar.

Hale Pohaku is at about 9000 feet, which is not terribly higher than the 6600 feet of White Rock. However, I had been living near sea level for a while, and I noticed the altitude after a few minutes of hiking around the fascinating collection of cinder cones in the immediate vicinity. At this altitude, rainfall is relatively low, so the vegetation is a tropical version of the pinon scrub I am familiar with from home. Paradoxically, Hale Pohaku is often fogged in. I'd say the cafeteria was immersed in fog about half the time I ate there, which was a tad disappointing, because of the picture windows gave a magnificent view to the south during clear weather.

Altitude sickness goes through several stages. Becoming easily tired with exertion is the first and most obvious. Sleeplessness is another. 9000 feet is well below the summit of Mauna Kea, and the reason the living quarters are here is to give you a fighting chance to sleep during the day. I found it noticeably difficult.

On our first night, we grabbed one of the Land Rovers required to reach the summit and drove on up. It didn't take long to break through the fog deck into the clear air above. The summit of Mauna Kea is desolate but breathtakingly beautiful. Quite literally. I decided after a day or two that it is the closest thing on Earth to the surface of Mars, except I swear that Mars has got to have more oxygen. Mauna Kea reaches nearly to 14000 feet.

One of the worst things you can do when you are trying to fight off altitude sickess is to exert yourself unnecessarily. Unfortunately, I can't resist ladders and catwalks at observatories. After about thirty minutes of exploration, my fingers were tingling and I had the beginnings of a pounding headache - the next signs of altitude sickness. Nausea soon followed; Mauna Kea is the only observatory I worked at where I did not make many visits to the freezer for midnight snacks.

Fortunately, I didn't quite upchuck. That's the next stage of altitude sickness. The next-to-last phase is respiratory distess, which puts fluid into the lungs and leads to a downwards spiral. The last stage is cerebral edema, which is usually fatal. The only treatment for either is rapid descent, which can be difficult in bad weather. Mauna Kea had a couple of fatalities shortly before my visit, and I understand that a baric chamber is now part of the complex. When I was there, the crude makeshift was a tank of oxygen in the kitchen. This became my substitute for midnight snacks. I'd periodically go get a blast of fresh oxygen to clear my head.

When I wasn't fighting off nausea or helping work the telescope, I would go out on the catwalk and watch the light show to the south. Kilauea was actively erupting forty miles away, and you could see the lava fountain from the catwalk of the CFH telescope. I tried to get a time-lapse photograph by bracing my camera against the rail in the 20-mile-per-hour wind, with predictable results: A crummy photo and a bad case of wind chill. It gets amazingly cold at night at 14,000 feet, even in Hawaii.

One curiosity of CFHT is that I don't remember the night assistant. This is probably because I only saw him briefly. The Coude room was so distant from the main control room that we communicated by intercom.

Another interesting characteristic of Mauna Kea is that it is exceedingly dry. This makes it a superb site for infrared astronomy. It also means that you consciously drink as much water as possible. The dry air guarantees lots of static, which computers don't like much. After we had to reboot the instrument control computer for the third time, Ann found some tinsel left over from the previous Christmas, wrapped herself in it, and grounded one end. This seemed to cure the static problem, but the sight of Ann decorated like a Christmas tree was ... something else.

I've not heard it emphasized, but altitude sickness can affect one's mental state. Ann started telling stories about the menehunes, the Hawaiian version of the Old Ones. Somehow, in crossing over from Hawaiian culture to European culture, these became mischevious little people, something like leprechauns, but a bit more sinister. So help me, the altitude had me in such a fragile mental state that I found myself hearing little footsteps behind me every time I went out on the catwalk. It honestly spooked the heck out of me.

Anyway, we finished our observations, collecting several tapes of spectrograms of the stars were were interested in, and headed back to California. Ann could never bear to let go of her "booty," so she always put the tapes in her carry-on luggage, reluctantly surrending it to airport security for hand inspection so that the metal detectors wouldn't spoil the data.

I had the task of figuring out how to do the analysis. The beryllium line is in a part of the spectrum that is full of other spectral lines, so it is hard to pick out and measure. I finally resorted to subtracting the spectrum from a reference spectrum that we believed had no beryllium - this worked surprisingly well. The results were presented at a conference at Meudon Observatory outside Paris, which gave me ample opportunity to practice my rudimentary French and to cure my francophilia. That's another story for another time.