Mike Brown's Planets: observing

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The long road to a Titan storm

Look in your newspaper this Saturday, and you may see a paragraph about Saturn’s moon Titan and a giant storm that moved across the surface last May and what that means. With luck they’ll even print it with a tiny little picture of Titan to catch your eye. Your response, if you have one, will likely be “huh.” It’s OK. I’m not offended. It’s hard to distill the richness of a full scientific paper into a paragraph. And it’s even harder, still, to distill the richness of a decade of scientific inquiry into a short scientific paper. But if you’re curious about what that little paragraph means, and how it came to be in your newspaper, and what we’ve been doing for the past decade, read on. It’s a long story, but that’s somewhat of the point.

I became interested in Titan ten years ago, almost as a matter of convenience. It was an excellent solar system target for the then-new technique of Adaptive Optics, which attempts to undo some of the effects of the smearing of starlight caused by Earth’s atmosphere. Titan was a great target because it is just small enough to be completely smeared by the atmosphere, but big enough that, if you could unsmear it, you would still have a nice view. Just as importantly, no one had ever had a nice view of the surface of Titan before because the satellite it covered in a thick layer of smog which mostly doesn’t let light penetrate to the surface. When the Voyager spacecrafts flew by, they took pictures of Titan which look like a big orange billiard ball. I should have said, though, that visible light doesn’t penetrate to the surface. On the earth, red light penetrates smog better than blue light (hence the nice red sunsets on a smoggy day in Los Angeles). The same happens on Titan. Red penetrates better than blue, but infrared penetrates better still. In fact, if you go far enough into the infrared, you can take a picture of Titan and almost not notice any smog there at all. Conveniently, the new technique of Adaptive Optics works best in the infrared. Hence Titan became a natural target to try out the new techniques on. Antonin Bouchez, then a relatively new graduate student at Caltech, signed on to do this project as part of his Ph.D. thesis.

Our first goals were to obtain maps of the then-almost-totally-unknown surface of Titan. And what a strange looking surface it turned out to be! We speculated endlessly about what all of those dark and bright spots on the surface might be (for the most part it is fair to say that we – and everyone else – had no idea whatsoever until we got better images from Cassini a few years later). And then, in late 2001, we found a cloud sitting at the south pole of Titan.

A cloud!

It doesn’t sound like such a big deal, except that it had long been predicted that Titan was incapable of having clouds. Occasionally there was speculation that clouds of methane might be present, but that, if so, they would be tightly confined to the equator. And yet there it indisputably was: a cloud at the south pole.

Antonin and I were so astounded by this that we put Sarah Horst, then an undergraduate at Caltech, at work looking through a tiny 14-inch telescope on the roof of the astronomy building at Caltech. We had developed some special telescope filters which would – we hoped – be capable of penetrating the haze deck and seeing if Titan got a little brighter due to a cloud or two. We wouldn’t be able to tell anything else, but that would be enough to go back to the giant Keck telescope and say “Look now! There will be a cloud!”

It worked. Just a month after our first cloud detection Sarah saw something that looked just like what we expected a cloud to look like. We called people at the Keck telescope and begged them to snap a picture, and there it was. A much bigger splotch, still near the south pole.

I’m an astronomer, not a meteorologist. I had to spend six months learning about how clouds worked, trying to understand precisely why people thought they wouldn’t occur on Titan, and figuring out what was wrong. On a long summertime flight across the country where we continuously skirted afternoon thunderstorms, it all came together: no one had ever previously bothered to consider the effect of Titan’s surface heating. Like Arizona on a summer afternoon, Titan’s surface can heat up and eventually drive convective clouds over it. On Titan, though, it doesn’t happen in the afternoon. It happens in the summertime, when the south pole spends something like 10 years in continuous sunlight.

It was a compelling story, and, I think true. But, even better, it made some fairly clear predictions. The clouds were at the south pole when we discovered them only because it was very close to southern summer solstice. Titan (and Saturn) takes 30 years to go around the sun, so its seasons are quite long. But if you had the patience to watch, you should see the clouds move from the south pole to the north pole over the next 15 years before coming back 15 years later.

Antonin eventually got his Ph.D. and moved on to take a job working with the technical team continuing the development of Adaptive Optics at the Keck Observatory. It was the perfect place to be. Whenever there was a spare moment or two at the telescope, he would swing it over towards Titan and snap a picture. The clouds were nonstop. Sometimes there were just a few tiny specks, but occasionally there would be a huge outburst. It was a thrilling show to watch.

Emily Schaller entered graduate school at Caltech at just about that time, and she decided to do her thesis on watching and understanding these developing clouds on Titan. The first year was exciting, indeed. She saw a monster cloud system cover the south pole of Titan and remain for more than a month (disappearing just as one of the first close Cassini flybys went in to take pictures; Cassini saw a few wispy little clouds but missed almost all of the action). Henry Roe, a recently graduated Ph.D. from the University of California at Berkeley who had been using the Adaptive Optics on the Gemini telescope to study Titan, moved down to Caltech to work with us, and the odd discoveries about the clouds poured in. They appeared to finally move north from the pole; they appeared tied to one spot at 40 degrees south latitude for a while; they untied themselves; bright clouds in one spot seemed to foretell bright clouds in another. It was clear that we were amateurs here. We enlisted the help of Tapio Schneider, a professor of environmental engineering at Caltech and one of the world’s experts on atmospheric circulations, to help us make sense of what was going on. Things were finally falling into place.

In one final piece of exceedingly clever astronomy, Emily Schaller replaced our clunky nightly observations with a 14-inch Celestron, originally begun by Sarah Horst, with a sleek set of nightly observations from NASA’s Infrared Telescope Facility on top of Mauna Kea. The IRTF would take a quick spectrum of Titan every night possible, and Emily could quickly look at the rainbow of infrared light to tell precisely how many clouds were there. And when they looked good, she could tell Henry Roe, who would get the Gemini telescope to examine them.

And then the clouds stopped.

For years and years Emily would look at her data in the morning and walk across the hall to my office to mournfully say “no clouds again last night.” Seeing no clouds is scientifically interesting, and she dutifully wrote papers and indeed an entire chapter of her Ph.D. thesis demonstrating and trying to explain this years-long lack of clouds. But, really, I understood. Explaining a lack of something is not nearly as satisfying as actually getting to see something happen. As her advisor, I would have been happy to fly to Titan to perform a little cloud-seeding, but no one had yet figured out exactly what chemicals or incantations might do the trick.

On April 14^th last year, Emily walked across the Caltech campus to finally turn in her thesis. Then she did what she did most mornings: she walked to her office, downloaded the data from the night before, and checked to see if Titan had clouds. That morning, I suspect, she came close to falling out of her chair. She was likely exhausted from those final stretches of thesis writing, and I am sure that the first time she plotted her data she did what I always do when I see something astounding: she assumed she had made a mistake. She probably re-downloaded the data, double-checked the coordinates, and shook herself a little more awake. But it was no mistake. Titan suddenly had the largest cloud system seen in years. She likes to say it was Titan throwing a graduation party for her. But I know better: I think Titan likes to hide its secrets as long as possible, and knew it was finally safe to let go.

The scientific paper that Emily wrote along with Henry, Tapio, and I that appears in Nature describes the big cloud outburst and its scientific implications. And the implications are pretty fascinating. This big cloud outburst – the biggest ever seen – began in the tropics of Titan, where it has been speculated that clouds, if they ever form, should be weak wispy things. The tropics are where, of course, the Huygens spacecraft that landed on Titan took dramatic images of things that look like stream beds and shorelines and carved channels. How could those be at the equator if there are never clouds and never rain? People asked.

This discovery doesn’t actually answer that question, because we don’t know why there was a huge outburst of clouds in the tropics of Titan. But it does perhaps answer that lingering question: How could those be at the equator if there is never rain? Because there is rain.

Now, however, I am going to allow myself to speculate a bit more than we were comfortable speculating in the scientific paper. I am going to ask: Why? Why were there clouds in the tropics? Why did they appear suddenly at one spot? What is going on?

What I think is going on (again, I warn you, rampant speculation follows…) is that Titan occasionally burps methane, and I think Emily found one of the burps. For many years scientists have wondered where all of the methane in Titan’s atmosphere comes from, and, I think, here is the answer. The surface occasionally releases methane. Call it what you want. Methane geysers? Cryovolcanoe? Titanian cows? Whatever happens, the methane gets injected into the atmosphere and, at that location, instantly forms a huge methane cloud. Massive rainout ensues downwind. The stream channels, the shorelines, and everything else in the otherwise desert-seeming regions are carved in massive storms.

Evidence? Evidence? Where’s the evidence? You scream. Fair enough. I am giving you a snapshot of how science is done, and, at this point, this is the hypothesis stage. Or hunch. Or speculation. This hunch is the type that then guides what we go off to try to observe next. What will we see? Will the spot Emily found burp again? That would be pretty striking confirmation. Will other spots blow? (I should mention that we do indeed think we saw a different spot burp a few years ago).

At this point we have observed Titan well for about 7 years, from the winter southern solstice until the northern spring equinox, which actually just occurred last week, the terrestrial equivalent of late December to late March. What will the rest of the year reveal? We’re still watching, waiting. Maybe in 23 years, when we’ve finally seen an entire season, we’ll call it a day.

Homeward bound

I’m on my way home today from a quick trip a third of the way around the world to use a telescope.

Astronomers are, of necessity, vagabonds. Sometimes the thing that you want to look at in the sky is only viewable from the southern hemisphere, so down to Chile you go. Sometimes the thing is so faint that only the biggest telescopes around are worthwhile, so it’s off to Hawaii. What’s rare, though, is to spend 24 hours flying from Los Angeles all the way to the Canary Islands – a group of high volcanic crags off the coast of Africa with a latitude almost identical to that of southern California – to use a telescope smaller than the one that is just a three hour drive from my house.

When, after a day of travel, I got to La Palma, the island whose highest peak is strewn with telescopes, and I stepped outside into the dark dark night sky, I was greeted with exactly the same sky that I see in Los Angeles. OK, there were many many more stars, but they were all in their right places, and nothing was there that I couldn’t have seen from home.

So why spend all of that time to travel to a telescope smaller than my local one when all of the same sights were visible? Because when it was night time in the Canary Islands the sun was still high overhead in southern California. And the thing I was hoping to see only happened right then. If I had stayed home and waited eight hours to look later I would have seen nothing.

Here is what I hoped to see: that night the funny oblong fast spinning dwarf planet Haumea was passing directly in front of one of its satellites (Namaka is its name). If I could determine precisely when it happened and how long it lasted I could learn many things about Haumea (its size and crazy shape, maybe also its interior structure) and also about Namaka (how big it is, how much it is being tugged around by the other satellite, Hi’iaka). But all of this was happening so far away that the only way I could tell when Namaka disappeared behind Haumea was that the total amount of light coming from Haumea should dip by about 1%, So at the telescope I spent two entire nights doing nothing but staring at Haumea and measuring precisely how bright it was every two minutes. For comparison, I also checked a couple of stars nearby at the same time. If they stayed steady while Haumea dipped in brightness I would know I was in business.

It all sounds so simple.

In reality, though, stars never stay the same all night long. They get brighter as they get higher in the sky and fainter as they drop. Even on the clearest nights they fluctuate due to changing atmospheric conditions. Seeing this tiny drop in brightness of Haumea in the face of all of this intrinsic variability is a tough task.

But I tried.

After two nights at the telescope I am leaving with my laptop filled with pictures of the sky and my hopes high. Did we see it? Did we detect this tiny dip which told us that Namaka disappeared? I think so. I have a plane ride from London to Los Angeles tomorrow to look at the data more closely and convince myself what might or might not be there. But I think so.

If we didn’t detect anything it’s bad news. Perhaps our predictions are off, or it’s just too small of a blip for us to ever really see. But if we did detect it then our work is really just begun. Turning that little blip in the sky into concrete information about Haumea and Namaka will take a lot longer than tomorrow’s plane ride. There will be many more such trips around the world to be in precisely the right place when it happens again. There will be detailed computer models of the exact time and depth and duration of the blips. There will be confusion and ambiguity. But that is all in the future. For now I have the simple pleasure of long uninterrupted plane ride where I can stare and poke at the data, catch up on some reading, and think about these dwarf planets. And at the end I get to pick up my daughter from school and she’ll ask “Daddy daddy daddy did you see any stars?” and I’ll tell her that I did, but that the stars here at home are always the very best ones in the sky.

Heavens above!

Almost ten years ago I got to be involved in an astronomical experiment. The US Air Force had recently completed a technologically sophisticated telescope on Haleakela, the highest peak on Maui, for the purpose of spying on satellites as they went overhead. The National Science Foundation was interested to know if the new telescope might prove useful for astronomers, too, so they recruited a few test cases to come see if they could make it work.

The tests were, ultimately, ambiguous. We were trying to observe Saturn’s moon Titan to see if we could take images of hurricane-sized storms moving across its surface. We were stymied as much by horrendously bad weather (on Haleakala, not on Titan), as we were by cultural differences between astronomers and the Air Force. (My favorite: our observations of Titan were temporarily classified, because “Titan” is the same word as “titan” which is a missle. The people doing the classifying thoroughly understood that we were observing the moon of Saturn but, by the rules, any observations of “[T]itan” were to be classified.)

But though we were generally stymied, one moment at that telescope will stick in my memory forever. We were waiting for Titan (the moon of Saturn) to rise high enough in the sky that night and watching over the operators’ shoulders as they spied on satellites. Whenever they were foreign satellites we were kicked out of the room. But whenever they were U.S. satellite we could stay and watch.

At 4am the night before, as we were driving down the mountain after a night of observing, we had listened intently to the news of the Space Shuttle parked at the International Space Station and the installations to be done that day. They were having problems, apparently, with getting a solar panel to unfurl correctly. We went to sleep not knowing what had happened. As we drove back up the mountain the next day we had still not heard any news.

Around 8pm, though, Elvis, one of the operators, said “ISS coming!” meaning that the International Space Station was soon to fly overhead.

“Hey, you guys seen the ISS before?” Elvis asked.

“Not that I know of” I said.

“This a sight to see; hold on.”

And the giant telescope swung to the horizon and started tracking the space station as it went across the sky and the other operator came in and starting making adjustment on the computer and then, suddenly, the Space Station came into focus.

It looked much like all of the other pictures of the Space Station that I had ever seen before with two exceptions. First, the solar panels were unfurled.

“Ah ha!” we said. “I guess they were successful last night.”

Second, we could see the Space Shuttle parked next to it. Every other picture I had ever seen had been taken from the Space Shuttle, so I had never seen what it looks like when the shuttle is parked right there.

The view was so good that if a spacewalk had been happening right then and an astronaut had turned around to wave at the earth we would have seen him well enough to know to wave back.

The telescope tracked the Space Station for about 4 minutes. When it was over, I picked my jaw up off the floor. It was, perhaps, the most amazing pictures I had ever seen a telescope make before, and it was just over our heads, rather than in the remote depths of space.

Only a few weeks ago, on these very pages, I tried to remind people to Look Up! To remember that stars and planets and galaxies are not abstract things that we read about but are real concrete and viewable things in the sky above. But, really, for most of my life, I’ve been just as guilty when it comes to those other things that occupy our night skies: the satellites. It’s not that I don’t see them all the time when I am looking at the sky, but I never think of them as anything more than spots of light moving across the heavens. Sure, I know all about the Space Station. I use the Hubble Space Telescope as often as I can. I think about the astronauts and the Space Shuttle and watch NASA TV to make sure the launch and the walks go ok. But somehow I still fail to make that cognitive leap that reminds me that these things are real, and are really in the skies over head.

Until this week.

Knowing that the Shuttle was up visiting the Hubble Space Telescope for the last time, I got an overwhelming urge to see them both, to somehow make a visual connection with the astronauts who are up there risking their lives so that people like me can continue to make astronomical discoveries. I knew that, in theory, you should be able to see such things, but I didn’t really know how. I did what any rational person would do in 2009, which is to search Google. And I found my new obsession: www.heavens-above.com

Simply tell the web site your latitude and longitude and it will tell you all of the bright satellites that will go overhead tonight.

I tried it the other night. The Space Station was making what I now realize was a particularly favorable pass. At 9:51pm I went outside (a full 2 minutes early, just in case, though I need not have). I waited. I traced precisely where I thought it was supposed to go and stared and stared just in case it was a bit faint to see in the glow of the Los Angeles skies. And then, precisely, on schedule, it silently and majestically moved from the southwest horizon to nearly overhead to the northern horizon over the course of about 4 minutes. It was brighter than anything else in the sky at the time.

I had seen it before, I am certain. But I had never seen it and known what I was seeing. I ran back inside and said to my wife Diane:

“I just saw the Space Station go overhead. It was one of the most amazing sights in the sky I have ever seen!”

She looked at me, nodded, and went back to the email she was writing.

OK. I get it. Satellites aren’t for everyone. But they’re out there. They’re real. They’re waiting. That bright light travelling across the sky contained three people who at that precise moment could have been looking down and seeing the crescent earth with the sun still illuminating the Pacific while California was now bathed in dark. Those people are really there.

As for the Space Shuttle, which set me on this mission, it hasn’t been visible yet. You can only see satellites when – like an airplane high in the sky at sunset – they are still illuminated by the sun while you are in the dark. By chance that has not happened over California yet while the Shuttle has been up. I might get a chance on Friday, when it is low in the sky around 5am. I will definitely wake up for it. It’ll be my last chance to see the Hubble Space Telescope and the Shuttle together and to remind myself that up there these things that we built, these people that fly to them, are all real, and finally on their way back home.

The occult sciences

Last weekend I had my first experience with the occult sciences.

Maybe I should rephrase that.

Last weekend I did my first occultation science. That’s what I meant.

Occultations are interesting events that can be seen here on earth. They are like miniature total eclipses except that instead of the sun being blocked, it is a star. And instead of the moon doing the blocking it is something else, an asteroid, a planet, a Kuiper belt ice ball. You know an occultation is occurring when a star suddenly disappears and then reappears seconds to minutes later. Something dark must have moved in front of the star.

Scientifically, occultations provide a unique glimpse at the dark object that is passing in front of the star. If you measure how long the star disappears and you know how fast the object was moving, you have just directly measured the size of the object. Or at least measured the size of the object across one line. To really measure the full size of the object you need more than one line. To do that, you station astronomers in something resembling a north-south string over the full expected size of the object. Everyone watches and carefully times the event, and then you combine all of the information to find out the real size and shape of the object. If you’re lucky, you might even detect that the star does not blink out, but fades out, instead. This fading shows the atmosphere of the object. If you’re even luckier, you might see a second disappearance of the star a little before or after the main event. You would have just discovered a moon of your object.

The occultation last week was by a large Kuiper belt object. Kuiper belt objects are so far away and appear so small from our point of view that the probability of one of them covering up a star at any point in time is quite small. Astronomers carefully track these Kuiper belt objects and carefully measure positions of stars over and over in the hopes that one of them will be found to occult.

Sometimes these predictions can be made months ahead of time and astronomers can prepare for the event. Sometimes, like for the one last week, no one knew for sure that the occultation would occur until a last set of careful measurements of the position of the star occurred a few weeks before. Suddenly it appeared that this occultation would be visible across much of North America and that the path would go over some of the major observatories: McDonald, Kitt Peak, Palomar, Lick.

With only two weeks to prepare, though, it is tough to suddenly get a telescope. All of the large telescopes are fully scheduled months in advance, but there sometimes some observatories have smaller telescopes that can be made available at shorter notice if you know the right person.

At Palomar, the right person to know if you want to observer on the brand-new 24-inch robotic telescope is me. I’ve been constructing this new telescope for an embarrassingly long time now, but it is almost finished and ready for real scientific observations. One of its major long-term projects is to monitor Saturn’s moon Titan for signs of major storm activity. But the telescope is still not quite ready yet; we hope to really have it finally commissioned by October.

But when we heard that this occultation was potentially going to be visible from Palomar we decided it was worth going up and trying to use this little telescope even though it was not quite ready.

…….

We arrived Saturday afternoon for the Sunday occultation. Emily Schaller – my now former graduate student (who moved to Hawaii last week to begin a new position as a Postdoctoral Fellow at the Institute for Astronomy at the University of Hawaii) – and I left Pasadena at noon, stopped once for coffee, and arrived at Palomar Observatory at around 3pm. We went right to the small dome of the 24-inch telescope, unlocked the door, and peered inside a bit apprehensively. No one had even been in side for the past few months as we were waiting for the final control systems to be finished. We knew that there was a moderate chance that something would have broken over this time period and the telescope simply would not work. We knew that last winter the dome had leaked. What would we find?

To our relief, everything looked fine. We plugged the telescope and the computer that controls it in and double checked that we could, at least, move things. We could! We set to work to get things going. We had brought some new software up on a laptop to control some important auxiliary functions. But we had forgotten to check if the laptop control ports were compatible with the telescopes, and, of course, they weren’t. We’d have to drive back down the mountain on Sunday to the electronics store and then pray we could get them to work on Sunday.

But still, we could at least try to make sure we could do some basic things, like point to things in the sky.

We did a few daytime pointing tests and, to our sudden horror, realized that the telescope did not move the way it was supposed to. When we said go north, it went south. East was west. Looking carefully through the software we eventually realized that someone the telescope was confused about who it was. It thought it was its [bigger] sister telescope in southern Arizona. Somehow the control software had been switched. The sister telescope had enough different parameters (like which way was east and west) to know that this would never work.

Frustrated, we went to dinner with all of the other astronomers who were at Palomar for the evening, and we brainstormed about how we might fix things. By the end of dinner we had decided that no fix was possible; we needed the right software.

We were in luck, though. Another of my graduate students was awake and looking at her email and realized what we needed and, more importantly, realized where we the software was. We copied it over tested things out, and realized that we were in business.

Because the telescope was not actually ready to be used yet, we had to do some very low-tech things to get it to work right. First, we found nice bright Jupiter up in the sky. Then we used a hand paddle to get the telescope pointing in approximately the right direction. Then I stood up on a ladder, looking down the barrel of the telescope, trying as hard as I could to line up on Jupiter while Emily took continuous pictures with the telescope’s digital camera. We finally meandered around enough that we found it (it helps that Jupiter is so bright that when you get even moderately close to the right place you can see the glow off to one side). Once we were at Jupiter, the telescope was smart enough to know the rest of the sky, so we quickly pressed a few buttons and the telescope automatically slewed to where our occultation was going to be the next night. We weren’t sure how accurate the slew was going to be, but, to our surprise, the star that was going to be occulted was right there in the center just as it was supposed to be. This might work!

We spent the next 2 hours pretending like it was Sunday night and doing exactly what we were going to do that night. Everything worked well except for the occasional problem we had when we forgot that one thing not quite finished yet on the telescope is the dome control software. We had to move the dome by hand to following the moving sky. Sometimes we forgot. We vowed to do better the next night.

………………….

The next morning we woke up and drove down to San Diego to pick up some computer equipment. On the drive back up the mountain we looked up at the sky and groaned. Summer thunderstorm clouds had completely covered the sky while we were going. It was possible that they would abate as the sun went down, but they looked pretty bad.

We got back up to the telescope, installed the new equipment, tested it, and realized, again to our thorough surprise, everything was going to work perfectly. Before dinner time, we finally stuck our heads out of the dome to see what the sky looked like. It was hopeless. The sky was 100% covered, and the possibility of observing at all that night seemed very very remote.

We went to dinner in sour moods and lingered over our deserts longer than usual, knowing that looking outside was going to make matters worse.

But we were wrong. When we finally forced ourselves to look, the sky was miraculously clear. Not a single cloud. I have no idea how it so thoroughly cleared itself in under 45 minutes. We ran back to the 24-inch, opened the dome (we had closed it, fearing thunderstorms!), and waited for it to get dark enough to find Jupiter. As soon as it was visible in the twilight glare, we swung the telescope, pointed it up, and punched in the coordinates of the star. Again, on the screen, was just the right field. It looked pretty crummy though; everything seemed too faint. Ah! The dome! We turned the dome in the right direction and everything looked fine.

It was 8:30pm. The occultation was predicted to begin in an hour, so we started acquiring the data, meaning that we took a picture of the star every 4 seconds (which makes many many pictures of the star). At about 9pm clouds suddenly appeared north of where we were, but we quickly realized they were heading even further north. Still safe. At 9:20pm we took one final look outside: not a single cloud. We then crowded in front of the computer screen to watch our pictures come in. At about 9:26 we started thinking that the star was getting fainter. But really? We made some very rough instant measurements and thought: yeah. Maybe. By 9:27 we were sure. Every single image showed the star consistently fainter. It stayed that way for 4 full minutes before getting back to normal bright again. We had seen it! At 9:40pm we sent a quick email to the other astronomers who were observing around the country. The subject line was “Subj: Report from Palomar: We saw it!”

Over the next hour other reports came in. Many observatories were clouded out, but a handful got good data. A quick comparison revealed that Palomar had, I think, been right down the center, giving the longest of all possible occultations. An even more careful look at the data revealed that the occultation was certainly not sudden; we had without a doubt detected an atmosphere around this Kuiper belt object.

We went to sleep, exhausted but thrilled. Heading back we realized that the sky was 100% covered in clouds again. We had just snuck in some clear skies at the right time.

Enough people had collected good data that useful information would come out of these observations. We would get a nice measurement of the atmosphere and whether or not it has changed recently. Looking at the atmosphere was one of the main hopes of the observations. The Kuiper belt object is currently receding from the sun and many astronomers suspect that its atmosphere will soon freeze out. Of course, only the very largest few Kuiper belt objects even have atmospheres, but this one has been known to have had an atmosphere for a while. The Kuiper belt object we were studying was Pluto.

Nervous gyrations

On Sunday May 11^th, at 6:53 PM, looking from my backyard, the sun will still be appealingly gleaming above the western horizon, with almost an hour to go before it sets. Almost straight overhead the almost-first quarter moon will be waiting to steal the show as soon as the sun is gone. But I won’t be looking at either one. My eyes will be focused just above the eastern horizon where my current favorite outer solar system object – 2003 EL61, better known as Santa – will just be rising. OK, so I won’t see anything but blue sky; even at night Santa is about 10,000 times too faint to see with the naked eye. But I’ll be looking that direction thinking about the fact that at that moment the Hubble Space Telescope will be joining our hunt for moon shadows. On May 11^th and then four other days over the following two week period, the telescope will come around the earth, swing towards Santa, and snap a quartet of pictures to help us determine precisely where the small satellite (aka Blitzen) is.

This is good news! Without the Hubble we feared that it would be another year or two before we figured out the orbit well, and in that time it was quite possible that shadows of Blitzen would no longer be falling on Santa. The case that we made in our emergency plea to use the telescope must have been compelling; within two days of sending in the proposal we had heard back that we had been approved. But there was some bad news, too. Hubble is approaching two decades in space, so things sometimes fail. Visits by the space shuttle continually fix the Hubble back up and add new capabilities, but with the space shuttle fleet itself barely limping along, Hubble has gone without a visit now for more than six years (a new visit is scheduled for late summer). In that time some of its gyroscopes have failed.

Gyroscopes are critical on a spacecraft like the Hubble, because they keep track of which direction is which. They work just like a spinning top works. As long as the top stays spinning fast it stays pointed in the same direction (in the case of a top that would be up); as the spinning slows the top starts to wobble and finally falls down. In space, with no gravity, the top would just keep spinning in whichever direction it was originally pointed. If the spacecraft does some maneuver to point in a different direction, the top still stays fixed pointing in whatever direction it started. Tops – which is all that gyroscopes really are – are great for space, because, with no gravity and no compass, there are not many other ways to figure out which direction you’re pointing.

If the Hubble had no gyroscopes left it couldn’t do anything. Luckily, three still survive. With three gyroscopes you can point anywhere in space at anytime. Wisely, though, the people who run Hubble decided that it was better to keep one in reserve in case one of these last three fails. So Hubble operates with two gyros. With only two you can still point to anywhere in the sky, but not at anytime. And this where the bad news comes in. After about noon on May 24^th Hubble can’t observe Santa again for a few months.

The people at Hubble wanted to know: was it still worth doing the observations? We had to ponder. We think Blitzen takes about 19 days to go around Santa. From May 11^th (which was the soonest we could get on the telescope) until May 24^th is only 13 days. So we won’t see the complete orbit, but we think we’ll see enough to be able to calculate where Blitzen is the rest of the time. “Proceed!” we said.

But then there was worse news. Hubble uses the gyros for course pointing, but for keeping the telescope absolutely still during the course of the observations it also tracks a pair of bright stars close to the target. And, by bad luck, there aren’t enough of them close to Santa. A single star is available up until the 19^th, and then absolutely nothing. We can do the observations, slightly degraded, with a single guide star, but there is nothing to be done after the 19^th. So now we were crammed into May 11^th through the 19^th, an eight day window, when we really had hoped for a full nineteen day window. They asked again: is it still worth it?

By luck, if you only had eight days out of nineteen, these might be precisely the eight days you would want. They are when Blitzen is closest to Santa, which is the part of the orbit we need to know best. But still, it’s going to make our lives even harder than before. Will it still work? We did some quick calculations and decided, once again, we could do it. So we’re on for our eight days in May.

Now I’m nervous. We promised a pretty spectacular result to the people at Hubble. We need to deliver. There is always the chance that the new data will show that the shadows just finished happening and we’re too late. That would be bad luck, but we could at least hold our heads high and say we figured it out, just a little late. No, what makes me nervous is the possibility that we will get the data and still not be able to figure it out. People will say: OK, what’s the answer? And we will have to say. Well, um, we still can’t quite calculate the orbit. We can’t tell you when there will be moon shadows. Wait until next year.

I don’t think this will happen, so mostly it’s just paranoia. And I always have it. Every single evening when I am sitting at big telescope and the sun goes down and the dome shutters open I get similarly nervous. What if we did something wrong and all of our careful calculations about what we are going to look at and what we might discover were wrong? What if we forgot to take something into account? What if there is a better way to be using the telescope? What if…

And then the sky darkens and our first targets appear on the screen and I forget all of the nervousness and worry and get to work.

The same thing will happen, I hope, with this project. I won’t be at the telescope this time. I’ll be sitting at my desk sometime a few days after May 11^th, when the data finally get transmitted and processed and downloaded onto my computer, and I’ll pull up the first image and forget all of the nervousness and worry and get to work.

Bluer still

continued from last week.

After lunch comes the final push for getting ready for the night. The support astronomers (astronomers who work at the observatory and who know much much much more about the telescopes and instruments than you could ever hope to know) arrive to help start setting things up for the night, the daytime crew at the summit does their final checkouts in preparation for the evening, and the astronomers (Emily and I) do the final mental and computational run through of the night to make sure everything is going to work out OK.

Emily and I are both paranoid about having done something dreadfully (or, even, trivially) wrong that will result in the loss of observing time. I think that such a healthy paranoia is one of the best traits an astronomer could have. Chances are, in fact, that you have done something dreadfully wrong the first time, and only by being paranoid enough to double, triple, and (with the two of us trying to out-paranoid each other) quadruple check do you actually get anything done. Today our paranoia results in the discovery of a bug in a computer program that we use to track the Kuiper belt objects across the sky. The bug causes the telescope to track a small fraction slower than it should. We fix the bug, do all of the calculations on paper with a calculator to make sure we really are getting the right answer, and then convince ourselves that we are indeed ready to go for the night.

Meanwhile, Jim, one of our support astronomers, walks in the room and casually says "oh hey we may be a little slow firing everything up this afternoon, as there was a power glitch at the summit just a few minutes ago."

Usually power glitches don't do anything, as most of the observatory runs on backup for short glitches, but, as we just learned, the laser, in particular doesn't. If I understood the explanation correctly, the laser almost draws more electrical power than the entire rest of the observatory. It has to be isolated on its own circuit. Luckily, the Hawaii Electrical Company (HELCO. At some point in the afternoon someone remarked "Add one more L and the name would be appropriate) essentially guarantees that there will be no glitches. Unluckily, this guarantee does little to prevent glitches.

Apparently, glitches are bad for the laser. I would tell you why, but I don't actually understand enough to tell you why. I am not an engineer. I tried building things with my brother -- who is an engineer -- when we were kids, and his were always fabulously designed and assembled constructions, while mine would always hang precariously for a while until they fell to the ground. At which point I could explain, in theory, why my design should have been perfectly good. Astronomers rely on a vast pyramid of highly skilled and highly creative people who understand all of these things we don't (laser physics, oil bearings, active mirror control, cryogenic mechanical operations, to name a tiny fraction) and who are dedicated to making them work.

The laser was not coming back up.

In any complex system like a Keck telescope many many things have the possibility of going wrong, so it is not unusual for there to be a little afternoon panic. We've learned not to panic. Emily and I, now fully prepared for the evening, spent our time watching the satellite weather image update every half hour. The huge mass of clouds to the west was slowing blowing our way, pixel-by-pixel. Based on how the clouds had moved over the past twelve hours, we were pretty sure that we would have a few good hours in the evening before they hit. And, even then, you never know. We have been at the telescope before when an impenetrably opaque bank of clouds mysteriously parted just as it reached the Big Island. So we still had hope.

In the background we could hear conversations taking place at the summit, between the summit and the small crowd gathered in the control room, and between some in the crowd and other people who had been called. It was a Saturday. The laser was not coming back up.

The first line of defense when something goes wrong is the set of people who are working that day. Yes, it was a Saturday, but Saturday had a night like any other day, so there were people working hard to make sure the telescope worked that night. But when the first line of defense fails, anyone and everyone can be called at any time of the day or night. In the background conversational snippets I could hear, I started to hear a common refrain. "I think we need Kenny." "Has anyone seen Kenny?" "Do you know where Kenny is the weekend?" Voices were beginning to sound slightly more panicky.

Kenny knows the laser better than anyone. If the laser is acting up, Kenny can calm it down. If the laser is not coming back up, Kenny will know what to do. But Kenny was not on call on Saturday. If someone is on call they are required to be a phone call away. Kenny could be anywhere on the island or just asleep with his phone unplugged. There was no way to know.

It was about this moment when someone slipped into the back of the room. He was wearing beach apparel, slightly sunburnt, and, frankly looked like he hadn't showered in a few days. If it weren't for the fact that I know that the building is locked, I would have guessed that someone had hiked the 15 miles uphill from the beach and was looking for a cool glass of water. Or, more likely, beer. Everyone turned around: "Kenny!"

"Sorry for the clothes, I've been out camping and just got the message on my cell that the laser is not coming up."

Everybody seemed greatly relieved. The voices all around continued. Emily and I went over plans and counter plans. The mass of clouds continued its slow march.

About an hour and a half before sunset, the Observing Assistant arrives at the summit. The OA is the one who drives the telescope all night long and makes sure everything goes smoothly at the mountaintop. Another piece of the pyramid. And, tonight, it is Cindy, one of our favorite people to work with in the whole place. Emily and Cindy and I have spent many nights together at the telescope (or at least she is at the telescope; we're still down in Waimea), sometimes working hard, sometimes trying hard to stay awake, sometimes playing silly games to distract ourselves from the fact that the night is slipping away and we're still not getting any work done because it is raining on the telescope.

As sunset closed in the conversations surrounding Kenny sounded up beat. The laser was almost there. It was going to be yet another afternoon of panic followed by smooth sailing all night long.

"What was THAT?" said Kenny.

Not a good question for Kenny to ask.

He asked Cindy, up at the summit: "Was there a power glitch?"

"Well, yeah, this afternoon," Cindy replied.

"No, I mean right now," said Kenny.

Cindy checked all of her systems, called other telescopes, looked everywhere, and finally declared, no. No glitches. This time, for once, HELCO did not do anything it wasn't supposed to.

But the laser was dead. And no one knew quite why. And to make things worse, the sun set. On a good night, we would, right now, open up the telescope, swing the dome around, and begin the night's work. Tonight, we were dead in the water, and there was nothing Emily or I could do. We watched the satellite image, recalculated the time that we thought the clouds would hit, and listened to the chatter in the background. We were not panicking at this point, but we were suddenly feeling extremely antsy. The sky was still clear for maybe two more hours, and our telescope was not even open.

We assumed that the laser would come up pretty quickly when suddenly one of the support astronomers asked, "Are you sure there were no power glitches? The entire adaptive optics system has lost power, too."

This whole adaptive optics system is sufficiently complicated that every single day it needs to be carefully calibrated to make sure that it is correcting the distortions of the atmosphere just right. Losing power meant that all of those calibrations had to start from scratch. Our first support astronomer, Jim, now joined by a second, Hien, set to work doing the recalibration.

Phone calls were made. Saturday night dinners were ruined. Evenings out were postponed. Everyone who knew things about the laser and the adaptive optics were called in from whatever they were doing.

I can't relay all of the different strings of conversations that were going on throughout the room. Neither Emily nor I were one bit of use to this, so we just stayed in the background, talking quietly, watching the clouds get closer and closer. At some point Kenny realized that not only were his Saturday night plans slightly modified, they might soon take a colder turn. Nothing was working and no one knew why, so Kenny decided he was probably going to have to take the hour long drive up to the summit for some hands-on work. The summit temperature hovers around freezing, so Kenny decided it would be best to take a shower and find some warmed clothes before he went. No one is ever really prepared for having to go to 13,000 feet when just a few hours earlier they were camping on the beach.

Jim warned us: "This is going to take at least an hour, in the best possible case. And I mean an hour from whenever the power is restored." Which was not yet. "Would you like to switch to a different instrument?"

As the sky was clear, Jim was offering us the chance to do something other than adaptive optics, which was better than doing nothing at all. We jumped up from our corner.

"Let's switch to NIRSPEC" I said to Emily.

NIRSPEC cleverly stands for near-infrared spectrograph, which means that we could use the instrument not to take extra-crisp pictures, but to analyze the light that comes from the object to see what the object might be made out of.

Switching to NIRSPEC was not in our contingency plan. The possibility that the sky might be clear but the adaptive optics system might be broken was so far down our list of possibilities that we never planned. Emily and I ran down the possibilities.

Me: "We can only look at the brightest of the Kuiper belt objects with NIRSPEC. What's up in the sky right now"

Emily: "2003 EL61 won't rise for about another hour. Quaoar will not rise until the end of the night. Orcus and 2005 FY9 are both up right now."

Me: "OK, we will not be able to do anything useful on Orcus in a short amount of time. I'd love to have NIRSPEC on Orcus for 3 nights in a row. But a few hours? Worthless."

Emily: "Agreed. OK. 2005 FY9? We have already analyzed much of the spectrum. We could collect more data to simply add it to what we have."

Me: "Boring. Let's try something new. There is a region of the spectrum that we've never looked at before. We never looked because we assumed there was nothing interesting there. But wouldn't you rather look somewhere new on the off chance that there might be something interesting that you hadn't thought about before than to look somewhere old to see it slightly better when you already know what is there?"

Emily: "That is only a moderately good argument."

Me: "Tonight I will definitely settle for moderately good."

Me, to Cindy: "Let's take the telescope over to 2005 FY9."

We got to the nice bright Kuiper belt object, began to collect data, and started to relax a little. The voices in the background were still a bit frantic. Even more people were in the room. But at least we were collecting new data.

Ten minutes after we started, the first cloud hit.

"Where did our object go?" Emily asked.

Cindy went outside to look, and it was true. Some of the clouds were arriving early. Even our desperation backup plan was not going to work very well.

The good news, though, was that the adaptive optics system was finally back up and running. The power had been restored after someone realized that one of the fans to cool the enormous power load of the laser system had not turned on after the initial power outage. A temperature sensor somewhere registered that things were heating up and shut everything down. This was good, otherwise all of the electronics would have been fried. But it was bad, because there was no obvious sign of what had happened except that nothing worked for a while. With some detective work and a few phone calls to people who thought they were going to have a free Saturday night to problem was found, the breaker switch was flipped, and the power came back on. The laser was still being massaged back to life by Kenny and company, but at least the adaptive optics system was going to work.

"OK, let's switch back" I said.

Part of Emily's Ph.D. thesis was the study of Titan with adaptive optics. Titan can be seen even though clouds, so at least this was going to work.

"The humidity is starting to spike" said Cindy's voice from the video screen.

Humidity. Argh. Telescope optics are delicate, so one does not want water condensing on them. If the humidity gets too high or if fog is around the telescopes must close immediately. I have been at the summit of Mauna Kea before on a beautiful clear night, walked outside, and in the slight moonlight been able to see that not a single telescope was open. Humidity. I'd rather that it just rained. Humidity is the worst. But as long as it stays low enough we were still ok.

"We are going to try not to think about the humidity and we're just going to go to Titan instead."

Jim chimed in, "We can stay open, but you should know that at moderately high humidity the lens in front of the laser has a tendency to fog up. We can then try to unfog the laser using the LLUD (Laser Lens Unfogging Device), but it doesn't work so well. If this happens we usually can't use the laser again for the rest of the night. We could for now install the LLCD (Laser lens covering device) that will keep the laser lens from fogging while we're not using it."

I asked what, exactly, where the LLUD and the LLCD. Jim answered, "The LLUD is a hair dryer. The LLCD is a large piece of plastic."

OK. If we have any hope of using the laser tonight we had better keep the lens dry. Let's do it.

Jim: "It requires pointing the telescope down towards the horizon and having someone stand up on the deck and place the piece of plastic up there. It'll take about 20 minutes."

Me & Emily: sigh.

Twenty minutes later, and about 3 hours after the sun set, we finally get to go to our first real target: Titan. But all of our staring at the satellite images had taught us one thing: the clouds were coming 3 hours after sunset. And our predictions were right. While Titan can be done pretty well though moderate clouds, we could barely see the thing.

Me & Emily: sigh.

After about 30 minutes there was word from Kenny: "The laser is ready to go!"

So at 11pm we were finally at full strength for the night, but the clouds covered the whole sky. We knew that the night was mostly lost, but we had hope that perhaps there would be a 30 minute sucker hole in the clouds that we could jump at. In just 30 minutes we could make a single observation of the positions of the moons of the Kuiper belt object 2003 EL61. Even one quick measurement would make us feel we had salvaged the night.

We swung the telescope to the position of 2003 EL61, watched the sky, and waited. Kenny kept the laser idling waiting to bring it up.

And we waited.

The satellite looked even more dismal than before.

A friend who was using the telescope in a few nights walked in to check on how we were doing. Our glum faces told the whole story.

"Do you mind if we use the telescope?" he asked.

"Can you do something useful in this mess?" I replied.

"Just maybe."

"Take it away. But we'll take it back if it ever clears."

Letting someone else take the telescope in really really bad conditions is a fabulous thing. Even with bad weather there is some residual guilt that I always feel about not taking data. Sometimes to assuage that guilt you take data that you know are worthless and that you will never use. But if someone else could possibly make use of the data all of your guilt is relieved.

My friend and his student then swung the telescope to the brightest star that they thought was interesting. The star was so bright that it could easily have been seen by eye if there were no clouds. But, now, the Keck telescope, the largest in the world, was having a difficult time even detecting it. Eventually the locked on and began to take data. We monitored how dim the star looked, and, knowing how bright it was supposed to be, could tell how bad the clouds were. In general the clouds made the star around 300 times dimmer than it is supposed to be. I suspect that they got no useful data throughout the night, either. But at least the guilt is now theirs.

By 3am I was tired and bored and the satellite image looked horrible. I gave up. I went to sleep.

Emily has more stamina so she decided to stay awake the last few hours. She promised to call if the sky ever cleared.

The phone never rang. The laser never fired. All of the people who sacrificed their Saturday nights to laser and adaptive optics were in turn sacrificed to the gods of weather. I apologized to and thanked everyone I knew who stayed and worked hard to make it happen for naught. No one seemed phased. Of course that's what they would do. Having the laser ready even on the slim chance that the clouds parted was the only thing that even occurred to them.

Astronomy is a pyramid, and, in this case, the pyramid is built on some pretty solid blocks.

People often ask: What happens if you have nights scheduled on the telescope and the weather conspires to prevent you from doing the project you had proposed to do? The answer: you can apply again next year. It is simply the luck of the draw.

We'll never know what we missed that night. Were the clouds on Titan doing something interesting (like the clouds on Earth were)? Where were the moons of 2003 EL61 that night? Could we have figured out what Orcus's moon was made of? We will apply again next year.

It's a long flight back home from Hawaii. Sometimes I sit on the airplane with my laptop salivating over all of the data that we collected. Sometimes I quietly meditate while thinking through the steps of the analysis that needs to be done. This time I slept. And I dreamt. And in my dreams the clouds parted, a bright yellow laser shot up into the sky, and the outer part of our solar system started to reveal its secrets.

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.

To be continued…..

Winter Rain and New Moons

The winter rains have returned full force to southern California after a two year absence, and the fact that they have come during the new moon is making me unpleasant company.

It’s not that I have any later were-wolf-like tendencies that cause moon-related outburst, nor that I believe in any supernatural connection between the rain and the moon, it’s just that the new moon is prime astronomical observing time and January is – or could be – a prime astronomical observing month. And the rain is stealing it away.

We’re still looking for planets, like we have been for a while, but this time things are a little different. We can see the final end of our searching in sight, and, this time, the final end will come not because we have finished looking everywhere in the sky, but because the camera that we have been using for the past 7 years is finally being retired in October. This impending retirement suddenly puts a new urgency in our searching, for any patch of the sky that we miss due to rain, clouds, fires, broken equipment, or anything else will remaining unsearched, potentially for years to come.

And we have had them, the clouds and rain (to say nothing of fires). Fabulous clouds and rain, even. In one weekend we got more rain than the total amount of rain my two and half year old daughter can remember over her entire life. She and I put on rain boots and walked down to the canyon below us, a place where we had been many times previously in her life, long ago with her asleep in a backpack, and, more recently lately, with her walking along beside until she tires. Last week, not knowing what was coming, I told her “Look there at those rocks! Sometimes when it rains a lot the water comes and covers them up and makes a river here!” So, during a brief lull in the rain, we went back down to the canyon to see, and the water was everywhere. You could have almost gotten by with a little kayak in the middle of the creek that was a dusty wash days earlier. “Daddy, water!” she said. “There’s water in everyone’s garden!” (She calls any park “everyone’s garden” which seems like an appropriate name to me). We found a shallow slow moving side stream and jumped and splashed and reveled in the water from the sky.

My point here is that I like the rain. Really I do. But, please, can’t we keep it confined to when there is a full moon? Every month there is about a week-long period centered on the full moon when looking for planets is simply not useful. Just like we need to avoid the bright lights from the city, which wash out the stars at night, we also need to avoid the bright light of the full. But, unlike the city lights, there is nowhere we can go to escape the light of the moon, so we have no choice but to close up for a week and wait for our search-light-bright nemesis to pass.

And then, for that week when the moon is full and the telescope is closed, then I really pray for the rain to come. Buckets of rain. Thunder and lightning. Frogs from the sky. Anything that nature can throw at us. During the week when I know the moon is full I look at the sky every night and revel in the clouds and precipitation and wish for more more more. My daughter and I giggle at the sound of the rain pounding the roof and marvel at the new drainage system we just finished installing which prevents the backyard from becoming a shallow inadvertent swimming pool. Give us more! Nothing is more fun than rain.

Nothing is more fun that rain, except when the moon is new. Then we have planets to find, and every cloud in the sky or forecast of showers several days off, or hint of a moist breeze blowing from the Pacific feels like theft. Part of the sky is being taken away, and I’ll never have the chance to look there again. It’s a strange theft; you don’t know for sure what, if anything you’re missing, much as if someone stole packages from under your Christmas tree that may or may not have had anything in them. In some ways, that theft is even harder to take, because the possibilities of what might be gone are almost limitless.

I’m not very fun to be around when it is raining and the moon is new. I would recommend avoiding me altogether. Or, if you must confront me, pointing out how nice the forecast looks in a few days. Or barring those, ask how my daughter is enjoying the rain. My scowl might break a little. But, really? Total avoidance is probably for the best.

Tonight, at least, the skies are looking clear. The last thing I’ll do before going to sleep is the same as the first thing I’ll do when I wake up tomorrow morning. I’ll walk out into my backyard just before sunrise and scan from horizon to horizon looking at the most prominent of the stars still peeking out of the brightening sky. I’ll scowl at any clouds that I see, and I’ll try to decide if perhaps they are just very local or short very lived or otherwise unproblematic. Or, more likely these days, I’ll step outside in the morning and see the whole sky covered in clouds, or I’ll feel raining coming down, or a thick morning haze will fill the entire LA basin. Then, as the gloomy sun begins to rise I’ll look right at the spot in the sky where we should have been searching for planets last night, and I’ll wonder what might have been in that now-stolen package and how many years will pass until finally someone gets to open it under their own tree.

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