A thoroughly sporadic column from astronomer Mike Brown on space and science, planets and dwarf planets, the sun, the moon, the stars, and the joys and frustrations of search, discovery, and life. With a family in tow. Or towing. Or perhaps in mutual orbit.



Blue Hawaii

The summit of Mauna Kea, on the Big Island of Hawaii, is considered one of the best places to do astronomy on the earth. At nearly 14,000 feet, the mountain top sits above much of the earth’s atmosphere; being far from any large towns, the island is isolated from many of the lights that ruin skies elsewhere; and, at a latitude of 20 degrees, Hawaii sits in a special band around the globe where clouds appear infrequently. But maybe not tonight.
It’s 11am, and I’m sitting in the control room for the Keck telescope – the largest telescope in the world – getting ready for a two night’s worth of work. I just woke up and had breakfast, sleeping as late as I could in hopes of being able to stay up all night tonight. I used to be better at sleeping late, when I didn’t have a 2 ½ year old waking me up early every morning at home, but, these days, I have a difficult time sleeping past 6am Hawaiian time, as that is already 9am in California and I would normally have been up for hours. Waking at 6am is bad, as that is about the time that I will be going to sleep at the end of the night of work. Luckily I have my grad student Emily Schaller here with me who, being fifteen years younger, is able to stay awake all night much better. On nights where things are going extremely smoothly or extremely poorly I have been known to lie down on the very comfortable couch in the back corner of the control room and, according to Emily, snore loudly.
The control room is a ring of computer screens. From where I sit at the observer’s main seat I have about 13 different screens in my immediate vicinity, connected to perhaps 6 different computers, with some of the screens containing virtual connections to even more computers. And, because that number of computers never seems enough, every astronomer always brings his or her own laptop to sit beside them, too.
On my laptop I am looking at the first thing I always look at when I arrive in the control room in the morning: the satellite image of the clouds over Hawaii. The sky is moderately clear right now, but a huge thick mass of clouds is moving across the Pacific reaching towards the islands. In the worst case, it looks like we might have only 8 or so hours before the clouds hit. The sun sets in seven hours forty four minutes.
Regardless of the weather, there is plenty for Emily and I to do to get ready for the night. We have to go on the assumption that the skies will become magically clear and be prepared, just in case. We need to sit down for about an hour to come up with our final strategy for the evening, with copious contingency plans for whatever the weather can throw at us.
1pm: The planning took a little longer than expected, mainly because we kept on trying to read the satellite image like animal entrails as a clue to the night. In the end, we decided that the images were about as useful at predicting as the entrails themselves, so we had to prepare for everything.
Tonight at Keck we are using a cutting-edge technology called Adaptive Optics that allows us to fix the blurring usually caused by the Earth’s atmosphere to get extra crisp images of our objects in the sky. One way to do this is to first shoot a laser beam from the telescope up into the sky to make our own artificial star. We then point the telescope directly at this star. This laser-star is blurring just like a real star, but we know what this laser star should look like, so we adjust the telescope about 500 times a second to keep the laser star nice and sharp. Conveniently, anything close to the laser star is now nice and sharp, so we can then take pictures of whatever we were looking for in the sky. The bad news, though, is that the laser won’t work at all through clouds. But, still, for bright enough stars in the sky, we don’t even need the laser to do the sharpening.
Here is our contingency table:
If the sky is clear at sundown we will fire the laser, test it out on a bright star, and then swing the telescope to the Kuiper belt object Orcus. Orcus is one of the largest of the objects out past Neptune, weighing in at a little less than half the size of Eris. Orcus has a little satellite (which we haven’t gotten around to giving a name yet) going around it once every 9 days, and our prime goal of tonight is to learn what the satellite is made out of. To do that we will analyze the sunlight reflected off of the surface of the satellite and see what spectral signatures are there. We need the laser sharpening to see the satellite, because the orbit of the satellite never takes out far enough from Orcus itself that we would be able to see it without. In fact, the satellite of Orcus has never even been detected from the earth before; all of our previous studies have been from the Hubble Space Telescope. We are extremely excited with the prospect of opening up this new window!
If the sky is not clear at sundown we can’t fire the laser, but we can use the sharpening on something bright. Emily is just finishing her Ph.D. thesis studying meteorological systems on Titan, Saturn’s largest moon. Titan is so bright that we can see it even through moderate clouds, and with the Adaptive Optics Emily will be able to pick out track the cloud systems in the thick atmosphere of the satellite to continue her studies. We’ll be disappointed to lose Orcus, but at least all will not be lost.
If the skies are clear near the middle of the night we will swing the laser around to the large Kuiper belt object called 2003 EL61 (which we have gotten around to naming, but the committee that is supposed to approve these things has done nothing in over a year as far as we can tell) which has two satellites around it. While we know the orbit of the outer larger satellite quite well, we have yet to determine the orbit for the inner satellite. We have hopes that just a few more crisp pictures will answer the question for us.
If the skies are not clear in the middle of the night we’ll continue Titan until 1am, when it sets, and then evaluate. If there is only moderate cloud cover, we will give up on Adaptive Optics and turn instead to trying to understanding the composition of the Kuiper belt object 2005 FY9 (also no name. Same story.) With the press of a few buttons we will swing a different instrument on to the back of the telescope and begin analyzing the sunlight reflected from this object.
Both 2005FY9 and 2003EL61 can be watched until the end of the night, but we have some hopes that if the skies are clear near the end of the night we will turn instead to Pluto. Pluto is (just barely) bright enough that we can do adaptive optics without having to worry about using the laser. Our main target of interest is Pluto’s largest moon Charon, on which, eight years ago, we discovered what we thought was evidence of past icy volcanism. We have an idea on how to really clinch the argument, but it will require some late night experimentation using the instrument in ways that no one has ever done before. That’s when astronomy gets extra fun.
2pm. Lunch time. Emily and I leave the control room and go down the road 5 minutes to Huli Sue’s Hawaiian Barbeque for some brisket. Down the road 5 minutes? I forgot to mention that the control room for the Keck Observatory is not at Keck Observatory. While the telescope sits above the barren moon-like landscape of Mauna Kea, the control room is at the headquarters of the observatory in the sleepy cowboy/astronomy town of Waimea at about 3000 feet above sea level.
I love Waimea. Most of the town is surrounded by the vast Parker Ranch, though the interior is growing. When I first started coming to the telescope almost 15 years ago Waimea was a one stoplight town. Now there are two. Sitting at the (new) Starbucks in town recently I watched as a well-dressed tourist with a Maclaren baby stroller held the door for a Paniolo wearing a cowboy hat and spurs while a well known astronomer walked in beside them. It is the place on the planet that I have spent the most place other than my home of Pasadena in the past 15 years. I’ve been here for the Hawaiian Princess Festival march through the center of town, and, best of all, the Christmas Truck Parade, which is a parade of decorate trucks for which the entire town turns out, whether they want to or not, because it goes on the only road through town.
How does it work that the control room is 10,000 feet below the telescope, though? When the control room was first moved from the summit a decade ago I, and many other astronomers, were dubious. How can you do astronomy while not being at the telescope? For years I had been trained to stick my head outside of the dome hourly to assess conditions and decide on what to do next. If you stick your head outside in Waimea it is likely to be pouring down rain while the summit it crystal clear.
But I came around. A 14,000 foot summit is a hard place to think straight, particularly when sleep deprived. I am a better astronomer at 4,000 ft than 10,000 feet higher. The communications with operators at the summit are by video conferencing that is sufficiently good that you often forget that they are there and you are here. And, since all astronomy these days is done by looking at computer screens rather than at the telescope, if you closed the windows down in Waimea you might forget that your control is not sitting up on Mauna Kea. Except that you could breath. And then you would be happy.
An obvious question to ask, though, is this: if we can be 20 miles away from the telescope, why not 2500 miles away? Why am I here instead of at home in a similar looking room with similar computers and screens and video conferencing? Technologically it would work, at least most of the time. Computer links between the summit and Waimea are indeed more reliable than between Hawaii and California, and, on the rare occasion that they fail (one night someone trench over one of the fiber optic bundles, for example), I have been able to quickly drive from Waimea up to the summit and not lose any telescope time. You couldn’t do that if you were in California at the time. But the real reason that I still spend so much time in Waimea is not so much technological as sociological. The people who know everything are here, and knowing them and what they do and when they do it and which computer they sit at when they do it can make the difference between getting good data and great data, or sometimes between getting no data and great data. If problems occur there can be a big difference between being a disembodied voice at the end of a video screen versus a live person who can stand up and walk over to talk to somebody. Though my wife is convinced that it is really for those quick afternoon trips to the beach, I really come to Hawaii for the people.
So off to Huli Sue’s Emily and I go. When we come back the support astronomers for the night will be in to be making their final checkouts and give us the word that everything is OK for the night. Except, as we will soon find out, nothing is to be OK with the night.

1 comment:

  1. Love it !
    Got to here from ABC Radio Science Show Australia - n.b. Robyn Williams should get a Nobel Prize for Science Broadcasting !
    Feel an affinity with where you are on side of Mauna Kea even tho' never been there. I spent 4 months on Maui and a number of times glimpsed the twin peaks on The Big Island from Haleakala's 10,000 feet - magic from 80 ? 100 ? miles.
    regards
    Michael Adam-Smith in Brisbane QLD

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