Mike Brown's Planets

This morning when I awoke and looked out past my feet, through the large glass door, across the swimming pool, and to the other side of the canyon, the first thing I noticed was the bright yellow color of the sunlight starting to move across the ridge. Yellow! It's the first yellow we've seen in a few days. No smoky gray, no deeply reddened twilight, just a normal yellow sunrise.

I got up and stuck my head out the door. No smoky smell. No ash. There was actually a coolness in the air.

Since Saturday, when the fire started, flames had approached within about 2 miles of our house, mandatory evacuations had crept to within 1 mile, and ash fell out of the sky like a gentle rain. But this morning it looks to be all over.

I'm going to keep my fire-watch ritual a little longer. Every other hour or so I walk over to the nine story building on the Caltech campus, go to the top, and examine the mountains for smoke. At my last check there was nothing at all, just a typical spring time green across the ridges. My eye traced over the deep cut that comes out to Eaton Canyon, went to the right to see the outline of the old massive 100,000 year old landslide, and found a tiny canyon that, on these scales, is almost not noticeable. At the top of the canyon, looking out over the ridge, is my little patch of the earth, still intact for now.

I had intended today to talk more about moon shadows and telescope strategies, but I'm distracted by Google Earth, satellite weather images, and LA Times updates.

Yesterday as I stepped out of the gym on the Caltech campus in the middle of the afternoon (Lilah's nap time is a good time to play squash), I looked up at the sweeping view of the mountains that greets you in many places in Pasadena. This time, though, the first thing I noticed was a plume of smoke coming out of a canyon to the northeast. Which canyon? I quickly zoomed in on some of the familiar ridges and valleys of the San Gabriels to figure out exactly how far away the fire was. How far the fire was from my house where Diane was home, Lilah was asleep. As far as I could tell, it was about 5 miles to the east of our house. Five miles is a long distance for fire on a day when the wind is essentially still. But still. I dropped my gym bag, fished through it to find the phone, and dialed home. Diane answered.

"Where's the fire?" I breathlessly asked.

"Um, what fire?"

This answer was probably the best she could have given. I now more calmly explained to her what I was seeing.

I got in the car and drove back to home. On the freeway you had a nice view, now, of a burning ridge. This fire was definitely not a little spot fire that was going to quickly get put out, but from there I could tell it was pretty far from our house. When I got home I pulled up Google Earth and tried to reproduce the exact view I had had from the freeway. I showed Diane. There. That ridge. Pretty far away.

Last night we had friends over for dinner and, as they got close enough to our neighborhood to see flames a few miles away, they called to say "Hey, isn't that fire kinda close to your house? Maybe we should have dinner at our house instead."

It was OK. Nothing was really close. I surreptitiously went inside now and then to check on the news web pages to see if anything was going on. Not really. Some hikers had to be evacuated. Some boy scouts had been temporarily trapped. The fire would be contained soon. I checked the satellite weather image, on which you could see the plume of smoke heading out to sea. It looked undiminished.

This morning we awoke to something now familiar. As night falls and air cools, the ash that has been lofted into the air all day long falls to earth. The ground was covered in gray flecks and bits. The smell of smoke had invaded the house through the windows we had kept open all night. The sun, rising to the east, on the other side of the fire, made a hazy red glow on the wall of the canyon we could see from our bedroom window.

The helicopters started early. We hadn't seen too many yesterday, but now there numbers were definitely increased. Fire trucks went screaming down the road below us.

Curious to see how far the fire had spread, I took Lilah -- still in pajamas -- and drove down the hill in the direction of the smoke. Whereas yesterday the fire was easily spotted and sharply defined, it was now tough to see anything through all of the smoke. I couldn't tell where it was, but I could tell it had grown overnight.

Sunday plans must go on. Diane had a work event and left. Lilah and I went swimming under the hazy sun. We ate grilled cheese sandwiches, played with finger puppets of the three little pigs, did a little roving hide and seek throughout the house, and finally Lilah went to sleep for her nap. Curious about the fire, I looked to see if I could find any news.

I guess there was a reason for all of the helicopters and firetrucks that seemed so close by. Houses were being evacuated. The fire was still out of control. I got out Google Earth once again to try to interpret what I read. The evacuations are all in the upper part of the city of Sierra Madre, the city immediately to our east. When I finally found the evaculation map I realized that houses 1 1/2 miles from ours were already evacuated.

It's not really that close. But still.

This time it was Diane's turn to call: "I just heard Sierra Madre's been evacuated; should I come home?"

"No. We're fine."

And we are. Really.

We live in a fire zone. Our house overlooks a wild canyon that is right now gloriously flowered, but come the hot winds of the summer and fall will be dead brown fuel. We do what we can. Our roof is fire resistant composite. We thin vegetation. Our swimming pool is connected to a fire hydrant on the street so that a fire truck could easily use the water to douse our lower neighbor's house (but not ours; it's only gravity fed, so it could only help the people below us; sadly, the house above us has no pool that would help us out similarly).

We have evacuation plans with multiple contingencies. Distant fire with plenty of time to plan? Pack both cars and take this this and this. Fire in the canyon right below our house? Take Lilah first, cats if there is time, and run like hell. What if the only road down the hill already has been overtaken? There is a trail behind our neighbor's yard that quickly goes down to a safe spot. Fire on all sides? Jump in the pool and breath through wet clothes.

We won't need any of these plans for this fire. They'll have it out tomorrow or the next day and, more likely than not, nothing significant will have been lost. It's the springtime. It's early. The plants still have some moisture left in them. The winds are not blowing. The real fire season has not yet begun.

These sorts of fires happen all the time in southern California. It will likely not rate more than a 4th page of the local news blip in the LA Times tomorrow morning.

But still. Right now Lilah remains soundly napping. Diane is at work wondering what is going on, and all I can do is sit and check the news sites, watch the helicopters to see how close they drop their loads of water, and stare at Google Earth and speculate on the interaction of slope direction, wind speed, and fire vectors.

Someday, presumably, it will be more. Plans will be put into action. We'll sit below with binoculars staring up at the hillside trying to figure out how close the flames have gotten. We'll call our home telephone to see if the answering machine picks up. For now, though, we do what we can, hope for the best, and always breath a little easier when the winds don't blow.

Tomorrow normal life will continue. Which, for me, means dealing with the technical aspects of our upcoming observations of the Hubble Space Telescope. Our proposal to search for moon shadows on Santa was accepted on Thursday, and observations will start in 2 weeks. That's what meant to write about today, before being interrupted by smoke and helicopters and fire.

Last week the clouds parted enough in the evening to reveal the just-set sun -- now already setting well north of where it was at the equinox just a few weeks ago-- with a tiny sliver of a new moon hanging like an ornament above it in the not-yet-dark skies. This sliver moon is, to my mind, one of the most impressive sights to periodically grace our skies. To me, the ethereal part is not the sliver itself, looking like a razor sharp sickle glowing in the sky, but the ghostly outline of the rest of the moon that can be faintly seen.

What is that ghostly outline? If you've paid close attention you might even have noticed that it disappears after a few days. By the time the moon is up to first quarter all you see is that bright sunlit half of the orb. It's hard to tell, because as the moon waxes towards full it gets brighter and brighter and you might just think that you're having a harder time seeing that ghostly outline in the presence of that brighter moon. But, no, the outline is indeed getting fainter.


What's going on? With a little thinking about what is illuminating the moon we can figure it out pretty easily and even make sense of the little details of when it is brighter and when fainter.

First, a few well known simple concepts. The moon goes around the earth (counter-clockwise when viewed from above the north pole), and half of it is always illuminated by the sun while the other half is not. The fact that we see sliver moons, quarter moons, and full moons is not so much because the moon is changing, as that our vantage point is changing. On those bright full moon nights we are seeing all of the illuminated side and the back is dark. When the moon is new we're seeing the unilluminated half, but if we could fly in to space to see the back side we would see it look full from there. Just like the earth, the moon always has a day side and a night side.

Now, let's assume that we're looking straight down at the north pole of the earth and that the sun is off in the distance at the 6 o'clock position. The moon is there in its counter-clockwise orbit. How can we see a full moon? First, the moon had better be in the right place. If the moon is at the 12 o'clock position, the part of the moon visible from the earth is fully illuminated by the sun, making it full. But that's not all you need; you will also need to be on a spot on the earth where you can see the moon. The best spot to be would be would be standing at the 12 o'clock position on the earth. That 12 o'clock position is in the middle of the dark side of the earth. It's midnight. If you're outside and you look up and see the moon straight overhead, you know it must be midnight.

You can also tell from this general idea when the full moon must rise and set. The earth, again viewed from above the north pole, also rotates counter-clockwise. Where are you standing when you see the moon on the horizon? At the 3 o'clock and 9 o'clock positions. But notice at these positions you can also see the sun in exactly the opposite direction. If you're standing in the 3 o'clock position and the earth is rotating counter-clockwise, though, the sun is soon going to disappear. Sunset! In the 9 o'clock position the sun is just appearing. Sunrise! The moon, when it is full, is doing just the opposite of the sun. So the full moon rises at sunset and sets at sunrise.

Let's try tonight's (Saturday, April 12th) moon as an example. We are about a day away from the first quarter. In about a week the moon will be full. Where is the moon? In the mental picture we have been painting ourselves it should be easy to see. If we see the moon only half illuminated, it must be in either the 3 or 9 o'clock positions. But we know the moon is moving counter-clockwise in its orbit and that it will be full soon, so it must be in the 3 o'clock position.

Knowing where the moon is immediately tells us when we will see it. Tonight, as the sun sets, look for the moon. The sun setting means that you are standing on the 3 o'clock position on the earth. The moon will be right over head in the sky. (note, though, that I'm ignoring the effects of latitude here. If you're at the north pole, the moon will never actually be overhead in the sky. So when I say overhead, you should take me to mean "as straight over head as it ever gets from where you live." From Pasadena tonight the moon will never get more than 12 degrees -- about the width of 3 hands held at arm's length-- from being straight overhead.)

Tomorrow night the moon really is at the first quarter. When does the moon rise, then? You will first see the first quarter moon when you are standing at the 6 o'clock position, directly underneath the sun. Noon. See if you can go find the moon rising in the east a little after noon tomorrow. To most people the appearance of the moon in the daytime sky is always a bit of a mystery. If you have ever felt this way, make tomorrow the day it is no longer mysterious by setting out to find it by knowing where it should be.

All of this brings us back to sliver moons. How can we see just a sliver of light? We must be seeing mostly the night side, but just a tiny bit around to the day side. If the moon were at the 6 o'clock position, we would see only the night side, and it would be new moon (and we would have the possibility of an eclipse; the reason they don't happen all of the time is that the moon goes around the earth on a circle which is slightly tilted compared to where the sun is, so most of the time the circles actually don't cross. ). A few days after new moon, though, when the sun is at, say, the 5 o'clock position, we should see just the tiniest sliver of the sunlit side against a mostly dark moon.

When does a sliver moon set? If you're standing at the 3 o'clock position, the sun itself has just set, and the sliver moon is low in the sky in the same direction that the sun just set. The sliver moon is always close to the sun in the sky, so it must set soon thereafter.

But wait. What about the glow? If the sliver moon is caused by just seeing a little of the sunlit side of the moon but mostly seeing the dark side, how could there possibly be a ghostly glow coming from the dark side of the moon? The side that is glowing cannot see the sun at all. How can we see it?

The answer comes from thinking about what the earth looks like from the moon. If you were standing on the moon and the moon were full, what would you see? You would be looking at the dark half of the earth. The lights of the major cities would fill the otherwise dark void.

What if there moon were at first quarter and you were looking down? You would see half of the earth illuminated, the other half dark. The people right at the line between light and dark would be the people for whom the sun were just setting. Those people could look straight up in the sky and see you standing on the moon.

Finally, let's look at the sliver moon. When we see only a sliver of light on the moon, people standing on the moon see only a sliver of dark on the earth. The earth itself is almost full.

When the moon is full the nighttime is so bright that you can walk around the wilderness without carrying a flashlight. If you were on the moon and the earth were full, the light in the sky would be nearly 60 times brighter (the earth is both bigger and more reflective). You could read your spacesuit repair manual without carrying any lights at all. The landscape would be illuminated the same as if it were twilight on earth.

And you would see that illuminated landscape from the earth. The part of the moon that should be dark would glow in earth light. When the people on the earth see a sliver moon, the moon sees an almost full earth. The dark side glows with earthshine.

The earthshine also explains, of course, why the glow starts to fade as the moon goes from sliver to quarter. By the quarter moon, like tonight, the earth appears quarter, too. There is only half as much light to illuminate the dark side. And in another week, when the moon becomes full but the earth is new, the earthshine is totally gone.

So while the crescent sliver is light that comes from the sun, reflects off of the moon, and then arrives at the earth, the ghostly glow is light that comes from the sun, reflects off of the earth, arrives at the moon, reflects off the moon, and then arrives back at the earth. The glow is the ghost of us. Tonight, when you look up at the quarter moon (directly overhead at sunset), see if you can see the remainder of the glow on the dark side. And wave at it. The light from your wave will travel up to the moon and be back again 4 seconds later and you'll be part of what I think is the prettiest treat to grace our skies.

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.