Here is part three of the travel diary about my trip to the James Clerk Maxwell Telescope on the Big Island of Hawaii.
Day 7/Night 4: Saturday, July 28
“The only constant is change,” said Heraclitus of Ephesus around 500 BC. This holds true for everything in astronomy, although it can take an extremely long time before certain changes become apparent. The Sun hasn’t changed much in the past 4.5 billion years, and likely won’t change much for another 4.5. One day, though, it will blow up and turn into a red giant.
Very young stars, of the type that I’m observing this week, change on timescales of about a million years – a blink of an eye for the universe, but an eternity by human standards. It doesn’t matter if I observe my baby stars today or tomorrow, or next week, or next year, because they don’t change that rapidly. Other objects in space can be much more variable. A particularly violent example is a gamma-ray burst. Typically lasting less than a minute, a gamma-ray burst carries more energy than the Sun will emit over its entire lifetime. The burst itself is followed by an afterglow at longer wavelengths that can last for hours or days.
Gamma-ray bursts are of interest for their unique properties – it’s hard to find more powerful explosions anywhere in the universe – but their short lifetimes make them difficult to observe. You never know when one might go off, and if one does, all telescopes around the world are likely busy doing something else already. This is why most telescopes have a policy that allows current observations to be put on hold in favor of short-lived targets like gamma-ray bursts.
At 1:15am this morning, Jeff (taking over from Jim for the last four nights) got a call from an astronomer at Rice University in Houston, Texas that a gamma-ray burst had been detected. We had no choice but to stop observing my project and point the telescope at the burst, hoping to catch the afterglow as quickly as possible. (The sooner the afterglow is observed, the better.) This required switching over from HARP to one of the other two instruments, which in turn required running a new suite of calibrations and standards. It took a little over an hour from when the phone call came in until we started observations of the afterglow, but that’s still considered pretty fast.
As violent as a gamma-ray burst itself is, the afterglow is extremely weak at the JCMT’s sub-millimeter wavelengths. We did a 3-hour exposure, but all we saw was background noise. As I said two nights ago, the lack of a detection is scientifically sill valuable, but given that we had to put my own project on hold for all that time, it would have been nice to get some signal. Curse you, GRB 20120729A, for messing up my night!
Day 8/Night 5: Sunday, July 29
Let me start off tonight by posting a short video I shot two days ago, showing the drive up from Hale Pohaku to the summit and a quick tour through the JCMT telescope dome.
Every night starts with the same ritual: open up the dome’s doors and roof, boot up all the operating software, run some quick checks on the telescope hardware, and execute a few standard observations to make sure the system is properly calibrated. While the operator does all of that, I plan the first set of science observations according to the current weather, source locations, and project priorities. The operator then either accepts my suggestions or comes up with an alternative. We try and plan ahead by an hour throughout the night, sometimes more, so that we can be as efficient as possible. The operator also needs the one-hour buffer to put in regular calibration checks and make sure the telescope is always pointing exactly where we want it to.
In addition to the video, I’ve also got some pictures from the end of the third night. When we were done observing, Jim took me on a quick tour past the other telescopes on the summit. Need I mention how beautiful a place Mauna Kea is?
Update 5am – For a good four-and-a-half night, we’ve been lucky with very stable weather and pretty much ideal conditions for my project. As of half an hour ago, that streak has ended. Patches of fog moving across the summit forced us to close the telescope dome and stop observing. Closing the dome is mandatory when fog shows up: we wouldn’t want all those tiny drops of water to get into the sensitive equipment. It’s unclear whether the fog will clear (haha!) before the end of the night, so we’ll be sitting idle for a while. That’s part of observing, too.
Update 6:30am – The fog is only getting worse. Even if it magically disappeared right now, it’s too late to still get anything done. We’re closing up and heading to HP.
Day 9/Night 6: Monday, July 30
More fog tonight. We’ve been at the ‘scope for about three hours now and have yet to open the dome. The weather forecast says the skies may clear later, but we don’t know when. This is shaping up to be a very long and boring night. Let me offer some entertainment by way of “Hotel Mauna Kea”, a parody of “Hotel California” produced by the staff at one of the other Mauna Kea telescopes a few years ago. The video includes a couple of scenes shot at Hale Pohaku, of which I haven’t shown anything yet.
Update 4:30am – The fog started to lift about an hour ago and for a while it looked like we could get something done after all. On second thought, the humidity is still more than 90% and the calibration data look terrible. We’re calling it a night.
Day 10/Night 7: Tuesday, July 31
Tonight will be my last night at the JCMT. As much fun as it’s been, I’m getting quite exhausted and am pretty much ready to head back home. It doesn’t help that we lost all of last night and half of the previous night to fog. The weather forecast for tonight says high humidity still, with some fog possible but not likely. The expected weather grade is 5, the worst one short of being unable to open the dome at all. My project calls for grade 3 weather, so I’m prepared for a night of observing other people’s projects in the grade 5 queue.
While Jeff is getting all the systems up and running, I stepped outside for a quick look at tonight’s sunset. Pretty, isn’t it?
Update 2am – It’s been a pretty miserable night so far. The weather has been hovering around the grade 4/5 boundary, a little better than expected, but not good enough for my project. In any case, we were overdue on some high-priority engineering and calibration observations, so that’s what we’ve been doing. No doubt it’s important for the ongoing accurate operations of the telescope, but exciting stuff it is not.
Worse than that, it looks like my body is succombing to the stress of working night shifts at high altitude for a week on end. I’ve had a headache for the past two hours and it shows no signs of leaving. I’ve advised Jeff and he said he’d take me back to HP if my head doesn’t clear up soon. He says he’s surprised I’ve lasted this long – most people here seem to work five-night shifts, so seven nights straight is unusually long.
Update 3am – The headache disappeared for a bit, only to return fifteen minutes later. The operator says he’s not going to take any chances; engineering-mode observations in grade 5 weather are not worth risking my health. In fact, not even top-level science observations in grade 1 weather would be worth it. If either the operator or the observer shows prolonged symptoms of altitude sickness, you shut down the telescope and head back to HP. In extreme cases, altitude sickness can be fatal. In my case it’s merely unpleasant, but I’m glad nonetheless that we’re heading down in a few minutes.