How To: Observe with APEX

Something I find exciting, interesting about a thesis on observational astronomy is the experience to learn how to use a variety of telescopes, often in stunning locations.  One purpose of this blog is to document the diversity in observing experiences, since each telescope, location, team has a story to tell.

Getting ready for observations at APEX.

Last week at APEX, circumstances obliged me to take the role of operator and astronomer at the telescope, and I had the privilege and responsibility to learn and synthesize the observing techniques and requirements.  My informal training consisted of watching over the shoulder of a staff astronomer for a couple of days at the telescope, and then following remotely via a virtual network connection to the telescope during the morning shift preceding my afternoon shift.  I took note of important commands, and planned my strategy for the afternoon.

When the time came, so did the adrenaline, and to add to the excitement of observing, I was stunned when the first command I sent to the telescope by typing "go" triggered an alarm!  In fact, it was just a warning that the telescope was beginning to move, as intended, and the operations went ahead.

Over the next few days, I learned by experience the observing routine, the quirks of the system, and methods to make the job simpler.  The most valuable lessons which will help me in the future were the general observing routine, which might also interest you, so I'll describe it here.

In the control room at the telescope. Who knows what to do now?

Observing routine
An observing routine includes several general categories, including set-up, calibrations, and science targets.

Set-up
We need to tell the telescope where in the sky we want it to point, and what frequency to observe.  To test this, we point to an object we know well, for example a bright planet like Venus, and make a few observations called pointing and focus.  We run scripts that tell the telescope to scan across venus, and calculate the corrections in each direction we need to make to get the best signal.

Calibrations 
When we observe, we are essentially measuring the intensity of light that arrives to the telescope.  To tell anything physical about our target (in our case, the molecular gas of a star forming cloud), we need calibrations to measure all of the stray light that leaks into the signal between our detector and our target region XX light years away.

For the ambient light in the sky, we observe a point in the sky that we expect to be free of any light related to our target.  This is our "off position", and we will subtract this signal from our "science" target observations.

But wait, closer to home, we need to understand the signal from our electronics and the path the light takes within our telescope.  For this we measure the temperature of the system electronics.  So in reality our detection will be (target+sky+electronics) minus (sky) minus (electronics) equals just target.

If we don't have the set-up and calibrations done right, our science observations lose their physical meaning.  Sometimes we even spend more time on the previous than the latter.

Science
Ultimately, what excites us is the detection of radiation from the "science" target that we are studying.  We can study just one point in the sky and integrate for a really long time, or we can make a map by scanning over a larger region of the sky and observing each point for a shorter amount of time.

Etc.
APEX observes radiation with wavelengths called sub-mm, which are longer than visible wavelengths but shorter than radio.  A sub-mm telescope can operate 24 hours per day, observing different sources as they rise and set all day and all night.  We can only observe regions of the sky above the horizon but not directly over head, and also away from the sun or we will fry the telescope.  We need to make a detailed schedule of what is possible to observe and when.  As we observe, a source is either rising or setting, so we can only observe a given source for a limited time, in this case we generally stayed on a project for a few hours.

Ambient weather, such as wind and precipitation can damage the telescope, and at some point I noticed a flashing red box on the control screen notifying me that the wind gusts were exceeding 20 meters per second (45 mph).  Had this wind sustained, we would have stopped observing because this grad-student-turned-antenna-operator didn't want to be held responsible for the antenna blowing away.  The telescope is designed to sustain the extreme weather conditions of the Atacama, and in fact we had no problems.

In practice
The control system has been designed to relieve many of these concerns and simplify the observing procedure, at least in theory.  Scripts made by engineers or astronomers responsible for a particular project tell the telescope the sequence of calibrations and observations.  Blinking red lights on the control screen generally mean that something is not right, and a vigilant operator can catch a problem before it manifests.

Even so, the observer might think that the telescope is happily observing, when in fact for some reason a setting is not right.  During observations, it's good practice to take a quick look at data as they arrive and verify that the observations are what we expect.  Of course, we don't know the exact signal we expect, or we wouldn't need the observations in the first place, but we have a general idea of the frequency and intensity of radiation we hope to detect, and where in the sky to point the telescope. If we don't detect anything, we can do a thorough check of the system and perhaps re-calibrate.  By understanding the entire system and environment, from detector on the telescope to source in the sky, we can be more confident in the detections that we report as science.

Somewhat unrelated, but I think these are the coolest things at 5000 meters, the "penitentes" ice formations.

Chile-time at APEX

Hola from the Atacama Pathfinder Experiment (APEX) in the Atacama Desert of Northern Chile!  APEX is a telescope with a 12m antenna that detects sub-mm radiation, or somewhat higher frequency than radio waves.  Operated by institutions in Germany and Sweden, as well as the European Southern Observatory, the observatory also adheres to the agreement that Chilean astronomers can use the telescope 10% of the time during the year.  This week is "Chile-time"!  

The observations:
We're actually coming to the end of our observing run, and it has been a busy one.  After two days feeling slightly under the weather and trying to keep a cold at bay, then two more days preparing a proposal for APEX observations during the coming semester, finally the cold AND the proposal deadline have passed, and I'm getting the hang of the observations, making the experience extremely fulfilling academically.  In fact, I'm not observing my own project all the time, but rather a series of projects proposed by Chilean astronomers which are in the "queue", one of these being mine, and each day we choose which to observe next.  This is an efficient way to run an observatory, because the observatory can optimize lots of projects that each have distinct set-ups and requirements, such as time of day/night and weather conditions.

The other day, short-handed for telescope operators, I took command of the telescope during the afternoon shift and ran the queue of observations.  I wonder if this is the most expensive piece of equipment I have ever been responsible for, with the least amount of formal training?  Feeling a great sense of responsibility and also recognizing the value of this unique opportunity, in a couple of afternoons I have learned the basic observing routine, as well as synthesized a lot of what I had learned previously about observations of this kind.  In a coming post, I will try to explain more about how to observe with APEX.

Other "observations" along the way:
APEX is located on the same Chajnantor Plateau as ALMA, at an elevation of 5000 meters, and one exciting part of an observing run at APEX is ascending the ALMA road each afternoon to begin observations.  On the way, it's possible to "observe" incredible views and even rare wildlife, on the lucky days.  Giant birds, giant telescopes, giant mountains and deserts.  The experience has been awe-inspiring at many levels and at every moment.

My ALMA turno recap

The sun sets on my final flight from Calama.

Officially, my "visit" at ALMA is finished. I completed the agreed upon three months and three "turnos" (shifts at the ALMA site in northern Chile) in January through April, with a bonus fourth turno in late April.  The experience has been entirely positive, I have had an insider's view of what it takes the raise an observatory and to begin operations at the largest observatory in the world!  There are still many complicated aspects of the observatory that are beyond my understanding, but every day I learned something new that I hope will help me soon when I propose to use ALMA for observations related to my dissertation.

Following a wet "altiplanic winter", ALMA became rather green.

I value the opportunities I had to travel to northern Chile, and live for several weeks in the "driest desert in the world".  In fact, we experienced rain storms, snow, and sand storms in the early months this year.  Now it seems that the weather is improving, and we were able to make observations that are only possible in a few places on earth.

Equally interesting to me were the people I met who are part of this incredible international collaboration between North America, Europe and east Asia.  In the control room I often heard English, Spanish, and Japanese, which happen to be the three languages which I have learned (and I hope I have occasion to improve my Japanese again!), some sort of strange coincidence that leads me to believe that everything we do and learn will have some purpose in our lives in ways that we cannot foresee.

The sunset was always impressive from ALMA.  Check out the time sequence, especially where the sun is setting relative to the mountain in the distance.  In January...

Late February...

And finally the sunset in April.  The sun is now farther north, meaning summer is over and winter is soon.  For you in the northern hemisphere, summer is coming your way.

I hope to maintain my connections to ALMA during the remainder of my time in Chile, so now I'll be splitting time between the ALMA offices in Santiago and the Universidad de Chile Department of Astronomy.  During my final turno at ALMA, I asked a few of the people I had been working with (astronomers, data analysts, antenna operators) some questions about their jobs, to get a better idea of what it takes to work full time at an observatory like ALMA, realizing that one day I may be in a similar situation.  You can find their responses in my astrobites post here.

Science! In memory of Michele.

I sometimes wonder what is is that makes me love what I do.  And, when people ask me what is the point of studying the stars and the universe, it makes the stop and think. 

This sentence seems to explain it all: "Science is the greatest of all adventure stories, one that’s been unfolding for thousands of years as we have sought to understand ourselves and our surroundings."   Read more of the article here.

Note: I found this article from a link that was sent by my friend Michele.  Sadly, Michele passed away last year.  The MD project is a digital scrapbook created by her friends, where the memories of her live on.

If you can't see through it ... ski through it

Easter sunrise behind the telescope.

Easter Sunday was quite non-traditional for me, but memorable nonetheless.  Actually, we had great weather for observing, and I made a lot of progress with my final observations, which ran from 5 am to 12 pm.  However, the previous couple of days hadn't been so good for observing, and I had spent some time staring out the window at clouds, snow, and skiers.  During that time, I vowed to ski before I left IRAM.  Finally, on Sunday, at 2 pm I hit the slopes!

View from the top.  Three things that I love in life: telescopes, mountains, and skiing.

I borrowed skis and boots from the observatory, which were probably older than I am, but fit almost perfectly.  I think you could call the observatory "ski-in-ski-out", because I just walked out the door near my room, clipped into the skis, and (after becoming re-acquainted with the skiing motions after more than a year of not skiing), I was gliding down the mountain.  Remember, it's April, which is definitely the end of the season here, so most of the snow seemed artificial, but at least well-groomed.  It was sunny and warm, and with clear skies, the view from the top was magnificent.

My transport down the mountain.

I returned to IRAM in the evening for a fantastic dinner, nice red wine, and good conversation with the other astronomers.  In the morning, the snow-cat took me down the mountain, and I'll spend the next couple of days exploring Granada.  A perfect ending to a very good observing run.  I can't describe exactly what IRAM was like, because the weather and conditions were always changing, and the contrast of the observatory on top of a ski resort in southern Spain's Sierra Nevadas is difficult to synthesize.  So, I will direct you to my photos, and these should give you some idea of my experience here.

Our only option to see the big picture

Perhaps you have read several of my previous posts, and I hope you have gotten some idea of why Chile is one of the best places in the world for astronomy.  For this reason, I have been thoroughly enjoying the experience (Thanks: Fulbright, U de Chile, ALMA, Yale) to live in Santiago this year, and work at the University of Chile and ALMA.  So why, you might ask, would I leave the astronomy-mecca that is Chile, and travel 7000 miles to seclude myself on top of this mountain in the Spanish Sierra Nevadas, where we happen to have been stuck in a snowy cloud for several days?

Sometimes we're above the clouds (at 3000 m elevation), and conditions are great for observing.  The sunsets are gorgeous too.

The telescope I am using is called the 30 meter telescope at the Institut de Radioastronomie Millimétrique (IRAM).  "30 meters" is the size of the telescope dish, and IRAM is an international research institute with headquarters in Grenoble.  Besides the fact that when I applied to use the 30m telescope, I was encouraged by the potential trip to Spain and a week of what I was told would be incredible cuisine, I wanted to use this telescope because it is one of the largest single dish telescopes that observes at the frequency at which carbon monoxide (CO) emits light.  This frequency of light is not necessarily what most people think of as "light".  If you looked at the CO in a star forming region with your eyes, you would see nothing, because the gas and dust are not hot enough to emit light at visible wavelengths.  However, the gas that forms stars is just barely hot enough (still, it is very very cool, only about 10-20 Kelvin, or degrees above absolute zero) to emit some radiation with wavelengths of about 1 millimeter.

They were actually observing through this.

 The IRAM 30m telescope is designed to detect this kind of light.  Why no shiny mirror? Don't you need a dome? How can you keep observing even when it's cloudy outside?  Radio and mm telescopes are slightly different than optical telescopes because the longer wavelengths of light don't need such a perfectly smooth, shiny mirror surface in order to be reflected and focused.  Also, the weather (as we obviously have wind, rain, snow here) doesn't do significant damage to the surface of the antenna.  And, we are lucky that we can observe even if it's cloudy or somewhat humid (although we have to be careful with the telescope if water, snow or ice accumulate) because radio wavelengths of light are longer than a typical water molecule, and therefore just pass right through (radio wavelengths can also pass through you and me, think about it).  Similarly, we can observe radio wavelengths during the day, because the light of the sun doesn't compete with our observations.  Very convenient... 

Check out these icicles on the telescope.  Skiers beware.

In fact, ALMA is also a "mm/sub-mm" observatory, and it can detect similar emission as IRAM.  But, the IRAM telescope is 30 meters, and the largest ALMA antenna is 12 meters.  With its many 12 meter antennas, ALMA has a large "collecting area" (think of it as many buckets scattered through the desert collecting falling photons), and it is very sensitive to faint light.  This is because the sensitivity of a telescope depends on its size, and with an array, the areas of all of the antennas contribute to the total sensitivity. 

Another important concept in observational astronomy is that the spatial scale to which a telescope is sensitive depends on the distance between any two points of the telescope.  In other words, an array of telescopes with large distances between any two telescopes (a.k.a. baselines) is sensitive to very small details. However, it is difficult for an array like ALMA to also be sensitive to the larger information (they don't want the antennas too close that they might collide).  For this we need single dish telescopes, where we can consider the infinitesimally small distance between any two contiguous points to tell us the bigger picture of what we are observing.

The receiver, behind the telescope dish, is where some magic happens.  Millimeter-wavelength light is converted to a frequency that a computer can process, and we can measure how much light we have received.

The heavy lifting (i.e. moving the telescope) is done with monster motors like these, inside the telescope mount.

Eventually, ALMA will incorporate a "compact array" and several single dish telescopes, at the same time as it functions as a large array that spans several kilometers, and we will have the best of both worlds.  But, for now, there is a bit of an art to carefully combining observations from a telescope array (we used an array in California called CARMA) and a single dish telescope like IRAM.  This combination magic will be my project after my observations end, so that hopefully we can make a pretty picture, and even more importantly understand the details of star formation on many levels. 

Cloudy and clostrophobic, but content

The amount of ground I covered getting here will soon be balanced by the amount of ground I cover each day.  That is to say, once you get to the telescope, there's no reason even to leave the building.  The commute to work involves two flights of stairs, and a short hallways.

I spent the last couple of days preparing my observations, and then learning how to observe with the IRAM 30m telescope.  Up to the last minute, we were deciding on a few crucial details of the observations.

One important piece of information for your observations is known as an "off-position", which is a position in the sky that you think will have very little (preferably none) light compared to your target source (at whatever wavelength you care about).  This way, whatever emission you do get from the off-position, you can assume is coming from the fluctuating atmosphere, and therefore correct your observations. Sometimes you just have to take a shot in the dark, or make an educated guess based on previous observations.

The other last-minute decision had to do with what's called "spectral resolution" of the observations.  You have a choice of how much detail you want to see, in exchange for the breadth of information you receive. Ideally you'd get both, but you can't have your cake and eat it too (an aside: they do feed us very well here, and that means multiple desserts every day).  The receivers needed to be precisely tuned to the specific wavelength(s) of interest, and if we tuned with very fine precision, we would lose some efficiency.

Fortunately, this is a very conducive work environment, with limited distractions, so I was mostly able to focus on the task at hand.  But, I occasionally caught myself peering out the windows at the changing weather conditions, and the occasional skier passing by.  And then I realized, I hadn't been outside in more than a day.  Some part of me thought, "Cool, maybe you should take the challenge, stay inside for a week straight, just to see what it's like."

It's totally feasible here, because we have accommodations, a kitchen (and wonderfully talented cooks), recreation facilities, and (of course) work, all in the same building, which is even connected to the telescope by a below ground passage. But, knowing that I'm atop a mountain at about 10000 feet elevation, overlooking the southern Spain Sierra Nevadas (even though we've been stuck in a cloud since I arrived), I just can't give into a silly challenge to stay inside the whole week.  I have to explore, I miss the feeling of sun and snow and wind on my cheeks.  So, at least I ventured outside for these photos...

At first it was so cloudy that I could hardly see the telescope.

The telescope sometimes appears to be peering towards the skiers as they come off the chair lift.

An older, smaller telescope is on the next peak.

Finally the clouds parted for a beautiful sunrise over the ski area below, and signalling the beginning of fantastic conditions for my observations.

20 hours

The past approximately 20 hours have been chaotic, but at least they have been linked by one common theme -- transportation adventures, with everyone else acting like it's all completely normal.  Here is the recap of the highlights in my journey to observe at the IRAM (Institut de Radioastronomie Millimétrique) 30 meter telescope.  The irony is that I will be using the telescope for a total of 20 hours over 3 days.

The adventure begins on board an Iberia plane, recently having taken off from Santiago, when it was announced that we would be arriving in Madrid at 8:00 am. Our itineraries said 7:00 am, and to complicate matters, the three others in my row and I had connecting flights at 8:00 am.  When one of the women (luckily the others spoke Spanish, and could vouch for me) asked the flight attendant how we would make our connection, his answer: "That will be difficult."  I told myself at that moment that there was no use in worrying for the entire duration of the 12 hour flight, and in the back of my mind I kept hoping that maybe the wind would carry us just 10% faster than expected.

Granada is in the Andalucia region of southern Spain.

We landed at 8:00 am, as announced, without one mention that we were later than the original itinerary.  Still holding out hope, I jogged through the Madrid airport, through immigration (luckily it was quick), and boarded the shuttle to the K terminal (the sign said it would take 18 minutes, but I kept optimistic).  All for nothing, because by the time I arrived at K, the flight wasn't even listed on the "Departures" screen.  Luckily, my half-marathon training had paid off when it counted the most, and I arrived near the front of the line at customer service.  Actually, it was very easy to switch to a later flight, I just passed my failed boarding pass across the counter, and without hardly a word, the Iberia employee gave me a new ticket for a later flight.

The problem was that my plan for transport to the telescope relied on the 8 am flight, to arrive in Granada at 9 am, and immediately take a van to the telescope (they had actually made special arrangements for me).  I found the words in Spanish to sheepishly say "I missed the flight", and I called the telescope to tell them I'd be later than expected.  From here, the adventure takes a turn for the better.  Beginning with the fact that people in Spain speak slowly and clearly, and I could actually communicate when it mattered the most. 

These bull cut-outs are seen all over the region.

I did arrive as per the revised schedule at 1 pm, took the transport to the observatory offices in downtown Granada, and from there a van about 1 hour to the Sierra Nevada ski area.  Slightly jealous of the skiers who will be enjoying their vacation during Semana Santa (Holy Week), but also realizing what an awesome experience it is to go to a telescope, I boarded the gondola (yes, everyone else was carrying skis, and I was carrying my luggage) which took me to the next ski station.  From there, I loaded myself and my luggage into a snow-cat, and we headed up the ski slopes to the telescope which perches on top of the hill.  That's right, next to a chair lift! 

Not my photo, but that's the telescope and our transportation.

The whole time, at every junction, the person accompanying me just waved me on to the next (progressively more strange) mode of transportation, as if (1) it was obvious that everyone rides a gondola to work sometimes, and (2) of course there's a gigantic 30 meter telescope sitting on the ski slopes.  And I went along with it, enjoying the ride, and looking forward to what will certainly be a unique Semana Santa.  It took 20 hours to arrive, who knows how many to return.  I hope the 20 hours of observations are perfect.

Turno #3 diversions

This turno got off to a delayed start, following an intense rain storm at the ALMA OSF (we hesitate to boast that this is the ``driest place in the world'' now).  Last week, the previous astronomers on shift were sent home early, and our trips were originally cancelled, then rescheduled a day later.  This meant that when I arrived at the OSF along with my supervisor, the first night we worked hard to quickly get the system going again and as many antennas as possible reinstated into the array.  Fortunately, the weather continued to improve throughout the week.  I hope this means the end of this year's "fuerte" (strong) altiplanic winter. 

After the rain, the mud dries into the most impressive formations I have ever seen (this is a parking lot that became covered in mud/dirt).  As the water evaporates, the sheets of mud crack and curl upwards around the edges.  A fun diversion can be to toss sheets of mud and watch them shatter into dust.  I have seen sheets several inches thick, and several feet long!  The desert is an amazing environment.

Each of the following nights, we had more and more antennas becoming available.  For various reasons, the array is always changing.  In this case, some antennas were being powered up after the storm, and others were being moved to a new configuration (unrelated to the storm).  To keep the telescope operating at very high precision, we need to know the exact location, focus, etc, of each antenna, and this process of measurements (called antenna integration) takes some serious time and attention.  Luckily, I was working with a good team and every night we made progress.


It wasn't always business as usual during this turno.  Here are a few notable distractions that kept things lively. 

Seen around ALMA -- The first is a video taken by the Project Scientist, just to show you that some creatures manage to survive in the harsh desert environment.  Creepy creatures like this one seem to do okay here.  Annoying flies and mice also call the ALMA site home. 

Visitors -- The ALMA Education and Public Outreach officer seems to stay busy coordinating visits to the ALMA site for journalists and photographers.  This weekend, we saw several new faces in the control room, including journalists from USA, France and Germany.  Of course, we had astronomers from, you guessed it, USA, France and Germany to talk with these visitors!  At first I was hesitant to be the USA voice for ALMA, since I too am only a visitor here.  At least I got to tour the North American antenna camp along with the journalists, and we saw one of the antennas being delivered by the transporter.  But, in the end, talking with the journalist made me even more excited about the project, especially the parts of this project that have never been done before, and it reminded me how fortunate I am to have this opportunity to work here. 

Also visiting ALMA was a photographer sent by ESO (European Southern Observatory) who is documenting telescopes for a book to celebrate the 50th anniversary of ESO this year.  He was photographing a group of us huddled around a computer that was controlling the antennas -- what we were doing could seem like a dull task, but actually it's exciting to be working with such a diverse group of people on a project that is always new.  One evening, we gathered a group outside for a photo with the sunset, and with Jupiter and Venus over our shoulders.  We were from Chile, USA, Japan, and Europe, personifying the agreement of the ALMA project. 

Getting outside -- We work a lot at ALMA, many hours spent in the control room staring at computers.  And while we accomplish a lot in that control room, I try to remember to also enjoy the incredible surroundings.  In all directions from the ALMA OSF are incredible views -- exploring around the ALMA site by day, or looking up at the sky at night. 

I went on two hikes with guys who work building antennas for ALMA, and who know the site very, very well.  We headed out walking north of the OSF, towards a giant cactus, and descended into a deep canyon that seemed to drop out of nowhere.  We followed the canyon as it wound through the nothing-ness, sometimes scrambling over boulders or hugging the walls of the rocky canyon to descend deeper.  To complicate matters, we had to avoid some pools of water after the recent rains, and the accompanying mud which always seemed to be some unknown consistency.  Fortunately, my new friends helped me along the way, I stayed dry and fairly mud-free, and I learned some more about the area, and about hiking in canyons (i.e. never go down somewhere that you may not be able to get back up).  I look forward to exploring this area even more.  Of course, next time I show up to our daily meeting after returning from a mid-day hike, I will make sure that I have cleaned the sunscreen and dirt off of my arms first…

Many years must have have shaped and rearranged the rocks in this canyon, like this boulder that we walked under.

It's not only the landscapes that are amazing here, but of course the sky is also impressive and infinite.  Last night one of the guys here set up a small optical telescope outside and we took a tour of the southern sky.  The highlights: a nebula in the Large Magellanic Cloud, a star cluster, the Sombrero Galaxy, the Orion Nebula and Saturn (okay, the last two are not uniquely southern, but they are especially awesome with such a clear sky).  We had spent several nights observing Saturn to calibrate the ALMA antennas, and to an ALMA antenna, Saturn is best seen as a spectrum with a little blip of light to signify a detection of the planet.  Exciting to us astronomers because it means the antenna is working.  But, not very aesthetically intriguing.  Last night, through the optical telescope, Saturn was more awesome than I have ever seen.  The rings were perfectly oriented, and we could even see the gap between the ring and the planet, several bands on the planet, plus several moons to the side.  It's good to remember that at its very essence, our research is really beautiful and somewhat mysterious, I think this keeps us motivated to continue exploring the universe. 

This photo of Saturn was taken with a camera pointing to the eyepiece of the 8-inch Celestron telescope. You have to see it to believe it.  Photo courtesy of an ALMA co-worker. 

Astrobites Post: An antenna array is a successful mix of apples and oranges

Here's my latest astrobites post, with some more details about the incredible ALMA antennas.  You'll learn about submillimeter interferometry, and why the 66 antennas at ALMA, built and operated by an international collaboration, make this the largest astronomy project in the world.

Did you know that the ALMA Array Operations Site (AOS) technical building is the second highest steel frame building in the world, at 5000 m?  If you can tell me what is the highest, I'll be really interested!

Real weather, simulated observations

We're nearing the end of the altiplanic winter here in the Atacama, which means (fingers crossed) we should get back to observing soon.  The other night we were very productive with observations, but last night was somewhat of a different story.  Snow at the array meant we were shut down for the night, limited to running the antennas in "simulation mode", which means we can test the software and the observing scripts, but the antennas only pretend to be observing (they're not supposed to actually move if there might be snow/ice on the surface).  So, the weather wreaked havoc on the observing plan, but it did bring some pretty dramatic (and admittedly incredible) scenes in the afternoon.  I tried to document it all.

(1) Sand storm -- In the time it took me to walk from my room to the control room, the sand storm blew by, probably about 10-20 km, which means it was moving about 60 km/hr (from my very rough estimates).  It fortunately didn't arrive all the way to the OSF (fortunately, because I hear the sand is impossible to dislodge from your ears, face, clothes, etc).  I wanted to capture the whole scene, because to the north was a thick cloud of sand, but to the south was still sunny and clear.  Above is the 360 panorama I patched together.  If you google something like "Atacama sand storm", you will see that this must be rather common after all, and produces plenty of intense scenes.

(2) Rain(bow) -- Every time it rains here, we head outside, just to feel the cool moisture on our skin.  Someone usually comments about how this should be the "driest place on earth".  Well, it did rain here, but it passed in less than 5 minutes.  Clouds in the direction of the antennas is not a good sign for the night, but at least the rain left behind a full rainbow.

(3) Cloudy (bad) sunset (good) -- Again, astronomers may regret to say that some cloud cover produces the most gorgeous sunsets.  Well, if we can't be observing, at least we can appreciate the beauty.  Here I was enjoying the sunset with one of the other astronomers on shift. 

(4) Snow vs. antenna -- An antenna makes the ~30 km journey from the OSF (3000 m elevation) to the AOS (5000 m elevation) very slowly and carefully, aboard the specially designed antenna transporter.  Any sign of weather, and the move is cancelled.  This afternoon, along with all of the other crazy weather that blew in, some snow arrived at the high site before the antenna, and the transporter was forced to turn around.  We (the astronomers and array operators) at least made lemonade from the lemon-y weather, and hung around to enjoy the show as the antenna was returned to its temporary home near the control building, where it will wait out the bad weather.  Check out more photos (uploaded on Picasa), and the video I took, but maybe it's better in fast-motion.  In case you're interested, the transporter has 28 wheels that can move independently, and can place the 100 ton antenna on its station with 1 mm of accuracy!!  The driver makes most of the journey in the cab, but for the final moves, the transporter is operated with a remote control (it seems sort of like a really exciting video game).   

... All of this exciting weather ultimately shut us down.  These were the most "real" things that happened, all within about 1 hour this evening, before we headed inside for the night of observing in "simulation" mode.  So, enjoy the photos and the dramatic stories now, and I hope that I won't have anything more to report of this nature in the future!!

ALMA at 5000 m

Feeling large and on top of the world.

This afternoon, fueled by little sleep but a lot of excitement, I had the opportunity to visit the ALMA antennas at the "Array Operations Site (AOS)", elevation 5000 meters (16,000 feet).  A fellow astronomer drove us -- me, and two Japanese astronomers visiting in the CSV group -- approximately 30 kilometers, along a wide, winding dirt road into the mountains.  Why so wide?  Because on occasion the antennas must travel along this road as well, on their special transporter, after being assembled or undergoing maintenance at the "Operations Support Facility (OSF)".  I won't bother to explain much more, but rather point you to the photos, where you can see the antennas currently at the site, as well as an antenna on the transporter down at OSF.

One thing I find completely incredible is how all of the antennas work together (you can see photos of the computers and correlators) to form one, large telescope.  In fact, the "L" in ALMA stands for "Large".  And, we are continually adding more antennas to the array, until full science operations commence in 2013 with 66 antennas!  I also realized when I was up at the AOS how much I love three things associated with astronomy (in one way or another): telescopes, mountains, and snowy landscapes.  You'll see all of them in these photos.

Turno NocTurno (Night Shift)

The sun will soon rise, signifying the close of my first night shift back at ALMA (Raul gets credit for the clever play on words for "night shift" in spanish -- "Turno nocTurno").  After a few weeks with the telescopes powered off, the good news is that we have 4 antennas functioning for testing purposes now.  The original plan was to have the antennas powered off and moved to their new configuration during February, giving the array team a chance to test certain components in the meantime (without the threat of extreme voltage), and bringing the antennas back to life at the end of February to start science observations in the new extended configuration. 

However, the "altiplanic winter" struck somewhat harder than expected, bringing unprecedented rains to the Atacama, washing away roads and damaging buildings (apparently construction in this area doesn't usually worry about being very weather proof).  The observatory was evacuated for a short time, roads had to be reinforced, cables re-buried and roofs patched before we were able to return to operations as planned.  All this happened while we were in Santiago...  Tonight was the first night of observations, and I could tell as we drove to the observatory that the area had seen some precipitation, because I saw green for the first time around here.  But, otherwise, I don't notice much damage.  The desert seems to have happily soaked up the extra water.

Greenery in the high plains, and snow in the mountains (volcanoes?)
in the driest desert on earth...

 Now, I'm left to decide how to structure my days.  My obligations are to be in the control room from 10:30 pm - 6:30 am, and I'll try to attend the daily group meeting at 3 pm.  Also fitting in a few hours for writing up my own research (trying to channel the good science vibes here), and hopefully some time for exercise and/or exploration around the site, I figure I can try for some solid sleep in the morning or the evening.  And I won't forget to take some breaks to step outside and enjoy the clear sky at night, and the beautiful sunrise over the mountains. 
 

Astrobites Post: My first “turno” at ALMA

Check out this astrobites post about my first turno at ALMA!  Throughout this year, I will try to post periodically in the "Personal Experiences" section of astrobites.com, specifically about current astronomy research in Chile.

The driest place on Earth, most days

The Atacama Desert is considered as one of the driest places on Earth. -- The ALMA website 

A lot of effort goes into choosing the site of an observatory, and science at ALMA will depend on a dry atmosphere.  For this reason, ALMA is located in the extremely dry Atacama Desert.  Extremely dry nearly the whole year, except during the "Altiplanic Winter", which brings precipitation typically in the month of February (see some snow on the top of the nearby volcano in the photo above).  As we near February, weather at ALMA can change quickly, and today we saw a storm blow in.  A weather report by the Ministry of the Interior and Public Security in Chile called for an "Alerta Temprana Preventiva por chubascos y tormentas eléctricas" (an Early Preventative Warning for Showers and Thunderstorms).  Big news, it seems!

When it began raining today, everyone stopped what they were doing to look outside in wonder.  Unfortunately, the antennas must be stowed during rain and snow, so our planned observations were interrupted.  We continued observing in "simulation" mode, meaning that we could test scripts, but couldn't physically operate the antennas.


At first one could feel discouraged that observations at the site which was thought to be the driest on earth actually were interrupted by precipitation.  Was there a mistake in the site selection?  However, by the reaction of the people here, I still believe that this inclement weather is rare.  Several astronomers and staff convened outside, beyond the protection of the roof, feeling the the cold refreshing rain on our skin.  Those who spend so much time working up here seemed rejuvenated just like the plants coming to life after a long dry spell.  

Coordinating so many people, and so many antennas

With hundreds of people working around the clock for years with the goal of creating the largest observatory in the world by 2014, it can be a challenge to make and track progress in this astronomical marathon.  Sitting in the control room for 12 hours each day, I see the hustle and bustle of many people performing many tasks, from telescope operations to antenna engineering tasks, often with success but occasionally with some failures as well.  It's important that everyone remain safe (for example, if someone is moving an antenna at the testing site outside, no one should walk over there unaware), that jobs are performed efficiently (i.e. two people don't perform the same redundant task unknowingly), and finally that jobs and problems be prioritized.  In a sense, communication is the key. 

Photos from almaobservatory.org

How do hundreds of people, each with different areas of expertise, communicate effectively?  One way is by creating layers of organization, including the ALMA board, management, committees, and teams of staff.  For example, I'm a part of the "Joint ALMA Observatory Science Team", and I work in the "Commissioning and Science Verification" group.  We meet every weekday at 3 pm to discuss the status of the previous day's projects, and plan for the day/night ahead.  It's certainly easier to get everyone together for 30 minutes and explain everything once, rather than having many small discussions which need to be repeated throughout the day.  Once per week, we have a Science Team meeting, when all of the groups come together for more coordination. 

The ALMA board in one of their important meetings in Santiago.  This room can connect via telecon to a meeting room at the OSF.

When I say "together", I mean this rather loosely, because at any give time, some of the team is in Santiago at the "Santiago Central Office (SCO)", while others are at the ALMA "Observations Support Facility (OSF)".  We connect via telecon, and it feels like one meeting room merges right into the other, only separated by a projector screen.  

Another innovative way that we stay connected and coordinated is via an online commercial software product called "JIRA".  The name is actually based on the similar bug tracking program "Bugzilla", which became called by the Japanese name for Godzilla, pronounced something like "go-jira".  How JIRA works at ALMA is that any time there is a problem that needs to be addressed, someone makes a "ticket" for the issue, and assigns the issue to someone on the ALMA team.  As the issue is addressed, it's important to keep good documentation in the form of comments and attachments on the ticket's website, and when the issue is resolved, the ticket is closed.  The tickets are helpful for letting others within the group, and also in other groups, what are the most important issues for developing and maintaining the telescope system (hardware, software, and anything in between).

Jumping into the CSV project head first, I was assigned several tickets and was able to determine their status, following the comment trail left by people who worked on the same problems recently (some of whom were visitors, or work elsewhere now).  Attached to the tickets were reports, programs, and information on how to access relevant data.  When the tickets were re-assigned to me, I even got emails from others who had been involved, encouraging me to ask questions whenever something wasn't entirely clear.  In this way, projects (especially long-term projects) are less likely to fall off the radar completely, even with many people working on many different projects, because the goal is to ultimately "close" all of the tickets in preparation for the fully-operational ALMA. 

The OSF Control Room is a very collaborative environment, and a great place to ask for help or explanation of the ALMA system.

Today I made my first JIRA comment, updating others on what I had accomplished (or rather, where I found a bug) with my project.  I'll keep working to fix the bug, with the goal of "closing" the ticket as soon as I can, and moving on to another.  I sometimes stop to think about how remarkable it is that ALMA can progress, considering the scope of the project.  But, when I think of the project as being comprised of teams with many dedicated and capable people, each closing issues one JIRA ticket at a time, I think that anything is possible. 

Chilean astro-culture

Tonight I'll highlight two recent news pieces relating Chilean culture and astronomy.  An observatory can feel isolated, but I enjoy the reminder that we're connected to the community, even when far away from the nearest city lights.  

From my experiences, Chile has embraced astronomy, and astronomy has embraced Chile.  When I say that I'm working for ALMA, I rarely need to explain to a Chilean what is ALMA, rather I'm told that ALMA appears in the news quite frequently here.  And, when I talk with ALMA astronomers about Chile, it seems that many astronomers make an effort to explore Chile and experience the culture and environment.  

The first news story, ALMA Observatory supports recovery of the Kunza language , I found highlighted on the ALMA Observatory webpage.  The ALMA Observatory is located in Chile's 2nd Region, which is important archaeologically because it is the site of several ancient cultures.  The Atacameño people comprise the 3rd largest indigenous population in Chile, and this article specifically focuses on maintaining several of the endangered languages in this region.

A traditional ritual performed at the telescope site in 2007 (photo from almaobservatory.org)

Second, and dealing more with popular culture in Chile, is the article Chile’s space wine Meteorito: the first meteorite-aged wine in the world (and for the bilingual: Observatorio chileno ofrece exclusivo vino hecho en base a un meteorito).  Considering that Chile is known for its wine, possibly more than it is known for its astronomy, the idea to create a wine aged with a submerged meteorite really "blends" the two concepts with marketing genius.  This article was sent in an email from an astronomer at European Southern Observatory, and it stood out amidst the other more typical emails announcing astronomy seminars and telescope status.  

If you know of other astronomical and/or cultural articles of interest, please do share!

On top of the world, and looking up

To explain ALMA, I will borrow the tagline from www.almaobservatory.org : "The Atacama Large Millimeter/submillimeter Array (ALMA), an international partnership of Europe, North America and East Asia in cooperation with the Republic of Chile, is the largest astronomical project in existence. ALMA will be a single telescope of revolutionary design, composed initially of 66 high precision antennas located on the Chajnantor plateau, 5000 meters altitude in northern Chile."

Driving to ALMA.  The OSF is an isolated community in the mountains towards the right.

The largest project, a huge international collaboration, and pushing the limits of astronomical technology.  To me it sounded fascinating enough, and that was even before I arrived to the driest desert in the world to begin my first shift at the Operations Support Facility (OSF).  To arrive at the OSF, I took a 2 hour flight from Santiago to Calama, an important mining city in northern Chile.  Then, an ALMA bus drove us two more hours, through San Pedro de Atacama (a dusty tourist town, with population of about 2000 people), up to the OSF at an elevation of about 10000 feet above sea level.


From the OSF, the telescope array (at 5000 meters elevation) can be controlled remotely, in addition to testing antennas, engineering, and other telescope operations.  The environment here is unique, with somewhere between 400 to 600 people "living" at the OSF at any given time, including scientists, engineers, telescope operators, and other staff.  I think it's a great work environment, considering that every single person here is dedicated to the operation of this observatory, 24 hours a day.  

My home for 8 days.

Several shifts, and many jobs go into making this telescope function.  For this week, I'll have a day shift, meaning I work from about 1 pm until midnight on several projects related to "Commissioning and Science Verification (CSV)" (in other words, making sure the telescope is working as expected) and "Early Science" (the first scientific observations to be proposed and made, now that a portion of the telescope array is in operation).  Others work night shifts, or morning shifts.  The dorms have shades on the windows, so you can sleep at any time of the day or night, and signs around the dorm buildings remind you to be very quiet at all hours.  In general, it appears very comfortable in the little ALMA village, with nice accomodations, a "casino" (which means cafeteria, in Chile), exercise facilities, and more.


I can give more details of what I actually do here as I get more involved.  For now, I just wanted to communicate some of my excitement in being involved with a project of such grand scope.  In the words of the ALMA Director, Thijs de Graauw: “We are living in a historic moment for science and particularly for astronomy, and perhaps also for the evolution of humanity, because we start to use the greatest observatory under construction at the moment.”