Sunday, April 17, 2016

Wednesday to Wednesday

I write this on the plane back to Santiago, to the "real world", whatever that means.  In general the shifts at ALMA are somewhat of a mystery to the outside world, and I get a lot of questions about what it's like.  What are we looking at with the telescope? How is it that we can observe the sky 24 hours per day? Am I camping out at 5000 m with the antennas? What, really, does an astronomer do?  This is a week at ALMA.

Wednesday at 2:30 pm, the taxi is waiting outside my apartment to take me to the airport. I feel like a scientific rock star every time my travel is arranged for me. I'm sort of technically already on duty today, and I used this morning to catch up on work, pack, and prepare to lock up my apartment for 8 days.

3:40 pm, flight from Santiago to Calama.  Calama is known for its copper mines, and it's not uncommon that the other passengers have hard hats as their carry-on luggage. Given this setting, I'm often one of only a few women on board.  I have noticed that more and more, the seats are also filling with tourists exploring the Atacama desert, with Calama as their gateway.

5:30 pm, we arrive at the Calama airport and I find the charter bus waiting to drive us to ALMA.  Actually I usually don't know the majority of the others on the bus, even though we work for the same project.  There are engineers, technicians, security, admin. And a few astronomers.

The desert landscape races past the bus window.  The ALMA OSF is the white spot in the mountains when viewed from here.  The antennas can't be seen from below.

7:30 pm, we drive up the dusty final stretch of the road to the ALMA Operations Support Facility (OSF). At the gate, with about 20 km still to go, everyone's ID card gets scanned and we are accounted for. Citizens of the ALMA camp. At the main office, a key is waiting for me, and I head to my room to unpack and rest for a couple of hours, before my shift starts.

ALMA camp.  We stay in these "containers" until the permanent residencia is built.

9:30 pm, I head to the control room. I like to arrive ahead of my shift, so that I can meet with whomever is on the previous shift, shadow them for a little while, get acquainted with the vibe of how observations are going, and hear the plan for the night.  I also set up my own laptop, catch up on emails, and of course make a fresh cup of coffee.  I pretend like it's my morning routine, except after the sun goes down.  Walking to work and seeing a spectacular sunset as the backdrop is worth any sleepiness behind my eyes.

The walk from my room towards the control room building.

10:30 pm, the night shift begins. Astronomers here divide 24-hours into 3 shifts: "morning" at 6:00 am - 4:00 pm, "day" at 1:30 pm - 11:30 pm, and "night" at 10:30 pm - 6:30 am. You can see we have some overlap, so that observations continue smoothly across all shifts. During the overlap we have time to share what's been happening, and what's the plan for the next 8-10 hours.  Typically 1 or 2 astronomers are on duty at any time of the day, and we arrive at the OSF either on Monday or Wednesday, so there is a constant flux of new and returning faces in the control room.  We are also connected with Santiago via a 3 pm meeting every day (although night shift is excused for need of sleep, and fewer join from Santiago on weekends), as well as a daily email report. This is a very coordinated effort.

10:30 pm - 6:30 am (or, a typical shift), What are we looking at with the telescope?  This is not the romantic "put your eye to the eyepiece and see what wonders of the night sky you can find," but the beauty is still there.  ALMA is a big project, and observing time is in high demand by astronomers all over the world.  Once per year (April), the Observatory advertises a "call for proposals", and teams compete to have their projects observed in the coming year.  This includes justifying the scientific merit and the technical feasibility of the observing plan.  These projects are ranked, taking into account a lot of factors including weather, location of the object(s) in the sky, duration of the project, technical aspects, representative balance of projects -- among European, North American, Japanese and Chilean teams--, and a little bit of luck.  

Our job, while on shift at ALMA and trained with the technical aspects of the system, is to carry out the projects in (roughly) rank order, make a first check of the data quality, troubleshoot when needed, and record the progress of a project so that high-quality data can soon be sent to the scientist somewhere in the world.  

The control room.  Somehow chairs tend to congregate.  Often people do too.  The astronomers and telescope operators work closely together.

We try to be efficient. I was told that the $1+ billion project, divided over the expected years of operation, equates to about $100,000 per day, or more than $50 per minute. These are taxpayer dollars from around the world being put into a pot for a single scientific project, but enacting the individually proposed goals of the scientific teams that these dollars represent.  I was pondering this, and I can't get over how incredible it is that this works.

6:30 am, my shift is over.  But observations continue 24 hours (with periodic breaks for engineering tests), and an astronomer for the morning shift has already arrived to take over. How is it that we can observe the sky 24 hours per day?  ALMA detects light with wavelengths longer than the light we see with our eyes, or binoculars, or an optical telescope -- the kind you might think of, with a glass lens or mirror.  These are close to radio wavelengths (the "M" in ALMA is for "millimeter"), and we are looking not listening.  All matter (hotter than 0 K) radiates light, and the wavelength is determined by its temperature -- shorter wavelengths from hotter objects, longer wavelengths from cooler objects.  The reason we can't see many stars during the day is because the brightest star radiating visible light in our sky is up at that time -- the sun.  But the sun is not such a prolific radio-emitter, and we can still detect the radio emission from whatever other objects are above the horizon.  Radio astronomy never sleeps.

The "radio" sky -- radio emission being emitted throughout the sky, day or night.
Image courtesy of NRAO/AUI

But radio astronomers still need to sleep, and now it's my turn.  First I head to "breakfast", which is now my dinner, before retiring to my room as the sun is rising.  Am I camping out at 5000 m with the antennas? No. Everything I have described during my shift has been at the OSF, at 3000 m.  Only the necessary engineers and security team work with the antennas at the "Array Operations Site" at 5000 m. In fact, I haven't even seen the antennas yet this year.  Sadly, we don't work in close proximity with the antennas, but they reliably send their signals to us via fiber optics. It may seem detached, but this makes the working and living environment much more bearable.  The brain doesn't function at full capacity any higher than 3000 m, and sleeping is hard enough even at this elevation.

Waking up to the sunset one day.
I set my alarm this week to 9:37 pm (feeling like odd numbers), although most days I wake up earlier for one reason or another -- mild elevation effects, hunger around mid afternoon when my body can't figure out why I slept through lunch, or just plain excitement.  In my off hours these days, I keep up with my own research, have a couple of telecons with collaborators, laze around reading and watching Netflix, exercise or make-shift yoga.  

10:30 pm, the night shift begins again, and I'll repeat this for 7 days-and-nights, until on the 8th day...

Another Wednesday, 6:00 am, I leave my shift 30 minutes early (thanks Erik and Kurt) so that I can quickly wrap up my work, pack up my computer, jump in and out of the shower, return my key and catch the bus at 6:30 am. It's dark, so of course I keep my eye on the stars over the desert landscape through the bus window.

At the gate they scan our ID cards and we are back into the world. We turn onto the main road and the ALMA camp begins to look like a small blur of dim light up in the hills.  I notice Venus making an impressively bright appearance over the mountainous (volcanous?) horizon to the east. 

Venus is the small dot in the sky, above the dip in the mountains.  San Pedro de Atacama sleeps below.

9:40 am, my flight to Santiago departs, and I spend the time in the air to write this post. Other times, I just stare out the window, with some good music as a soundtrack, and take in the impressive Andean landscape from above.  I'll be at the SCL airport in under 2 hours, with a taxi waiting, and I'll return feeling like a rock star astronomer once again to my own quiet little apartment.  My "rest days" begin, but I know that ALMA operations carry on.