On astronomy and international relations

Photo of James Bond filming at Paranal in 2008, photo courtesy of ESO.

It was in Chile that I first became passionate about astronomy in 2008. During the REU at Cerro Tololo Inter-American Observatory, we had an opportunity to visit several of the major observatories in Chile, including the European Southern Observatory (ESO) at Cerro Paranal, coincidentally just weeks before James Bond would be filmed at the observatory's residencia.  Astronomy in Chile was gaining world-wide notice, and at the same time I was contemplating what to do with a liberal arts major in physics, minor in economics and an interest in international relations.

My first visit to Paranal, learning about astronomy in Chile in 2008.
Behind me are some of the 1.8m ESO telescopes.

You probably know where this led me -- to pursue a PhD in Astronomy at Yale, Fulbright fellowship and year in Chile.  I find myself fortunate to follow a path which returns to the places where my passion began.  Recently I had the opportunity to travel to Paranal again, this time with several ALMA astronomers.  Our goal was to learn how Paranal operates and how ALMA might aspire to operate once the construction and commissioning are complete.  ALMA and Paranal are two great examples of international projects, based on a worldwide effort of scientists and governments working together, with the goal of investigating the physical secrets of our Universe.  In other words, physics, economics and international relations.

In 2012, I spent about 6 weeks at observatories, all the time observing light with wavelengths of about 1 mm, also called millimeter or sub-mm wavelengths, so my visit to Paranal was an opportunity to become re-acquainted with optical astronomy.  While the mm/sub-mm telescopes look like giant satellite dishes, the telescopes at Paranal use giant mirrors enclosed within domes.  Paranal has four 8.4 m telescopes called the Very Large Telescopes, as well as several 1.8 m telescopes, which can work together to comprise the Very Large Telescope Interferometer.  With an ESO scientist and interferometry expert, we toured the telescopes and interferometer lab, and we watched the scientists at work in the control room.  We asked a million questions about optical interferometry; of particular interest to us were comparisons with interferometry at longer wavelengths with ALMA.

An 8m mirror...

...inside one of these giant domes!

Paranal is run very efficiently, a joint-effort of astronomers, telescope operators, engineers, computer programmers, and other staff.  To give you some idea, there seemed to be about 10 astronomers and operators working in the control room at the beginning of the night, with decreased demand as the nights' observations progressed smoothly. During the day was time for engineers and programmers to maintain the equipment, or for astronomers to catch up on science projects.  We heard that it took years for many of these operations to be stream-lined following the construction of Paranal in XX, giving hope to the scientists at ALMA where construction only began a few years ago and inauguration is planned for March 2013.

Isolated from the nearest city of Antofagasta, about two hours by bus, the location of Paranal ensures very dark skies, and the facilities provide a very conducive work environment for the staff and visitors. The blast of humidity as you step into the residencia will rejuvenate your desert-dried skin, as the lush indoor greenery and swimming pool will also refresh your senses.  I was impressed by a photo exhibit featuring work by ESO astronomers, as well as professional artwork in the lobby. Small touches like these acknowledged that astronomers are people too.  For the creative, artistic or spiritual guests, there is also a music room, theater, gym and non-denominational chapel on site.  Three square meals a day at the cafeteria, and cookie cabinets in the control room, sustained the necessary scientific and extracurricular endeavors.

The residencia at Paranal, an oasis in the desert.

I only had the opportunity to spend one night at Paranal, but I enjoyed very much the first-hand account of how a major observatory operates.  A successful observatory seems to depend equally on human and technical capital.  Paranal certainly does have cutting edge telescopes, with multi-ton structures, perfectly polished mirrors and precise lasers.  To make all of this function, it also has trained personnel from many countries (in this case, mostly Europe and of course Chile), who are passionate about their work and their working environment.  ALMA is one degree more international, considering that ESO, which runs Paranal, is one of three partners, including North America and East Asia, in collaboration with Chile.  In the control room or cafeteria at these observatories, it's not uncommon to hear several languages, or to strike up conversations about careers and experiences around the world.

Although my day-job usually finds me staring at a computer screen in a more urban office environment, my experiences at observatories, often in foreign countries and among remarkable landscapes, remind me of the multi-faceted lure of astronomy, which I consider the greatest example of international relations and scientific endeavor.

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.