Stargazing in Hawaii (part 2 of 4)

Here is part two of the travel diary about my trip to the James Clerk Maxwell Telescope on the Big Island of Hawaii.

Day 4/Night 1: Wednesday, July 25

Woohoo, my jetlag is doing great and woke me up at 4:45am this morning. We’ll be observing until 6 or 7am tomorrow morning, so I’m looking at 24+ hours up and awake. Better try and get a nap in the afternoon. In the meantime, I’m heading to the kitchen to forage for a sandwich or something.

Update 4pm – I napped for maybe an hour, but there’s only so much napping I can do in the middle of the day if I’m not actually tired. I’ll just see what happens tonight. If I fall asleep, I’m sure the telescope operator will wake me up so he can make fun of me for being such a weakling.

So, how does this observing business work? Well, there’s me, the telescope operator (Jim for the first three nights), and the telescope. The basic game plan is that I tell Jim what to observe, and he executes those observations. As the telescope gazes at the sky, Jim and I keep an eye on the quality of the incoming data to make sure they can be used for science. Jim also makes sure the telescope remains highly accurate by measuring standard stars every two hours. How do I decide what to observe? Well, I just pick from a pre-approved set of projects. Each project has very specific requirements, for example on the weather conditions (mostly the amount of water in the atmosphere) and on when the target sources are visible. (Most stars rise and set just like the Sun and the Moon do.) I’m here for one project in particular, but if the current weather is better or worse than required for that project, I get to choose from a list of other available projects.

The JCMT can observe during the day, but conditions are better at night for the type of science we’re doing. We’ll typically start each night around sunset and end around sunrise. Safety regulations regarding work at high altitude dictate that we can only spend so many hours at the telescope each night. Some of the targets in my project will only be up at the end of the night, so we’ll go up a little later than usual to catch them.

Update 9pm – At least, that was the plan, but a power glitch forced us to go up early and make sure everything is alright. As it turned out, not everything is. The telescope is equipped with a couple of different instruments, each capable of doing different kinds of science. All instruments are cooled with liquid nitrogen and helium to very low temperatures, which much improves the quality of the data. The power glitch knocked out the cooling system on the HARP instrument, which is the one we need for my project. This is normally easy to fix – basically flip a few switches and wait for the temperature to drop – but tonight we seem to have hit upon an unfortunate string of events. No matter what Jim tries, HARP refuses to cool down. Jim’s been running back and forth all evening, talking about the JT valve (ah!) and the DAIKIN compressor (oh!), and mostly all I understand is that this has never happened before and it’s complicated. We’ve put my project on hold and we’re observing another project with another instrument. Fingers crossed for HARP getting back online later.

Update midnight – Jim’s attempts to fix the cooling on HARP remain unsuccessful, so it looks like the engineers will have to come in during the day and figure out what’s wrong. We’re continuing with projects that don’t require HARP. At least the weather is stable and we’re getting good data.

A few minutes ago, Jim cheerfully noted that we’re halfway through the shift. I’m pretty tired and have a mild headache, so I’m sure the remaining six or so hours will be major fun. Jim is keeping my spirits up with some wild tales from his days as a submarine commander in the US Navy. Apparently there’s nothing like a fire while submerged under the polar ice to separate boys from men.

Update 6:30am – Longest night of my life. Dead tired. Leaving the summit now and heading for bed.

Day 5/Night 2: Thursday, July 26

The instrument specialists worked hard all day to nail down and fix the problem with HARP, putting aside whatever else they had planned (such as a scheduled day off) and making HARP their top priority. HARP won’t be available for use yet as it will take all night to cool down to its operational temperature, but Jim is hopeful that we’ll be back in business tomorrow night. For tonight we’ll work with the other two instruments.

I woke up at 1:45pm today after six and a half hours of fairly uninterrupted sleep. Jim and I went up to the summit at 6:30pm to start our second night. The road from Hale Pohaku to the summit climbs 1400 m (4600 ft) in 13 km (8 mi). The final 5 km (3 mi) below the summit are paved, but the initial stretch up from HP is not. That initial unpaved stretch is, without a doubt, the worst road I’ve ever been on. It’s uneven, badly rutted (think washboard), and full of potholes. It’s steep and narrow, and occasionally shrouded in clouds. When driving up or down around sunset or sunrise (which is pretty much unavoidable), there’s the risk of heading right into the low-hanging sun. We avoided that particular problem yesterday by going up early, but today we find ourselves on two stretches with the sun straight ahead at eye level. The safest way to continue is for Jim to stick his head out the window and keep an eye on the side of the road to make sure we don’t veer off. There’s a reason that visiting astronomers like myself aren’t allowed to drive to the summit themselves.

Ever the optimist, Jim points out that the original road, back in the 80s and early 90s, was single lane only for most of the way, and all around more dangerous than the current one. He also claims the potholes on the dirt road up to his ranch are way worse. I counter that some of the paved roads in Michigan are worse still. Jim keeps our four-wheel drive truck at a steady 40 kph (25 mph), skidding and bouncing up the slopes of Mauna Kea. At some point we come across a couple in a regular sedan. Jim curses at the stupidity of taking a two-wheel drive car up past HP and drives them off the road to teach them a lesson. (No, not really, except for the cursing.)

Update 3am – Feeling less tired than yesterday, but still about five hours to go before we’re done. No signs of altitude sickness yet; maybe I’m just not sensitive, or maybe it helps that I’m drinking plenty of fluids. Of course, the downside is that I need to go to the bathroom every hour.

Update 5:30am – No matter where you point a telescope, you’ll always measure something. In most cases, however, you’re just picking up background noise. The signals astronomers are looking for are usually weak, requiring long exposure times. (An hour is not unusual.) At the same time, telescope time is expensive, so you don’t want to stare at a single target for longer than necessary to get a good signal. The problem is, you never know exactly how strong the signal is going to be. (If you did, you wouldn’t have to observe it.) If the source signal is weaker than expected, it can happen that you end up with background noise only. Tonight we’ve been unfortunate in that all observations have shown noise only. That doesn’t mean we wasted a whole night, because it’s still useful to know that something isn’t there, but it does make for boring times. A nice signal every once in a while offers more excitement than background noise.

Day 6/Night 3: Friday, July 27

As we were wrapping up at the end of last night, Jim took me on a tour through the telescope dome. We climbed up all the way to the roof, where we had a magnificent view of all the other telescopes on Mauna Kea, basking in the early-morning sun. I also got a closer look at the JCMT itself.

Standing on the roof of the JCMT, looking down on the Goretex fabric that protects the telescope from the elements.
The telescope dish measures 15 m (49 ft) across. On the left you can see the Goretex shield. The grey stuff is dust.
Rear view of the dish.

It’s a little past 8pm now and we’re back at the summit for our third night of observations. HARP is still having issues. We may be able to use it later tonight, or we may not.

Update 11pm – HARP is back in business. Let’s see what it can give us…

Update 7am – Nearing the end of a very successful night. The weather was stable as a rock and HARP worked great, allowing us to gather a lot of data for my project. More of that next night, please! Time now to close the doors on the telescope and head back to Hale Pohaku. We’ll take a scenic detour past the other telescopes for some more photo opportunities. Stay tuned!

Continue with part 3…

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