July 13, 2024

I, Science

The science magazine of Imperial College

In the fourth part of our Diary of a researcher series, Josh Greenslade gives us an insight in to what life is like at an observatory 2,800m above sea level. One thing is for sure: not even making coffee is easy up there.

In the fourth part of our Diary of a researcher series, Josh Greenslade gives us an insight in to what life is like at an observatory 2,800m above sea level. One thing is for sure: not even making coffee is easy up there.

Swearing at the coffee machine

It was after the 5th electric shock from the coffee machine that I began swearing violently at 4 o’clock in the morning. This is entirely understandable: I was tired, confused, hungry, annoyed, and just wanted a rejuvenating cup of coffee, a feeling I’m sure most of us can relate to. Of course, it wasn’t just the poor machine’s fault. At 2,800m up the Sierra Nevada mountain range, the humidity is exceedingly low and static electricity builds up a lot easier than at sea level. These shocks are an unfortunate by-product in the life of a modern- day-astronomer.

I had come to the IRAM 30m millimetre radio telescope to observe a galaxy that existed only a few hundred million years after the big bang. In particular, I was trying to observe the emission from cold dust in the galaxy: iron, carbon, and silicon based molecules, which are believed to have formed during the last stages of a star’s lifetime and, subsequently, permeate the galaxy. Such cold dust, around -250 degrees Celsius, has to be observed at wavelengths of several hundred microns, stretching from the far infrared into the few millimetre range.

telescope and astronomy building surrounded by snow

Water is the main absorber of starlight in the atmosphere. A good, rough estimate is that if there is more than 5mm of water in a column drawn between the aperture of your telescope and space, your signal will be entirely attenuated. All in all, this means that most modern telescopes are built in the driest places possible: The tops of mountains like the IRAM 30m on Pico del Veleta, ALMA in the Atacama desert, or Mauna Kea in Hawaii.

What this means for you personally, however, is that if you ever visit an observatory you tend to get static shocks. A lot.

Life at the telescope

Life at the telescope is no longer governed by the semi-romantic idea of the astronomer sitting with his or her assistant, recording their observations through the lens of a telescope.

Almost all observations done today are controlled by a computer.

Before you visit, you are required to create a simple program which controls the telescope, tells it which source to observe, for how long, and any other special considerations you may require, like a specific polarization of the light. Having a computer do all this for you is beneficial in many ways: you can track the exact position of a source as it moves across the sky, automatically adjust for changes in the atmosphere, and it will warn you when something is about to go terribly wrong. Indeed, it is primarily for this last reason, that astronomers are still required at the telescope. Cables can get tangled as the telescope circulates, wind speed can pick up, threatening the stability of the telescope, meter long icicles can form on the rim of the telescope and drop onto the panels, or worse, onto an unsuspecting PhD student walking under it.

block of ice with clear sky    iram sign covered in icicles

All astronomers operate in teams of two at the observatory, primarily to keep the other astronomer alive; altitude sickness, even at these heights can kill and any symptoms are treated as a medical emergency. That being said, the first few days you spend at the observatory you almost always feel slightly light headed and elated. The amount of oxygen at these altitudes is less than at sea level, and as such even a single set of stairs can leave you feeling like you’ve just run a mile.

Feeling high up high

This is also why you tend to code your program before you visit rather than during. It’s very easy to make a simple mistake at the observatory that will ruin your observations. The upside of this is that it is nearly impossible to do work that requires focus whilst you are there, and for this reason Netflix binges are often and extensively required as well.

Perhaps the strangest thing to get used to at the observatory is having to operate on multiple time zones at the same time. Local events, like breakfast or car lifts, are all run on local time, whereas your observations, governed by where on the sky your sources are, are run on UTC. It is strangely disconcerting having to think it is both 1 and 3 pm at the same time, and when people ask you what time it is, you require them to clarify more precisely what they mean. Combine this with the sleep deprivation from having no regular sleeping pattern, operating a 12-hour-shift on the telescope, jet lag from your flights, lack of oxygen, and stress and confusion from your observations not working correctly, observational trips are less of a relaxing getaway and more like a week-long visit at your parents.

Still, there is something wonderfully serene about standing, isolated in a snow drift, at the top of a mountain, the clouds hundreds of metres below you, watching the sun rise over the mountain peaks in the distance. Observatories are still romantic in their isolation, far from most other civilisations and alien in the way that you have to operate whilst you are there.

You are personally humbled that you are there to try to solve unique problems about the nature of the Universe, and understand something no-one else before has.

Truly, both practically and academically, you feel like you are alone at the top of the world.

I gave up on the coffee in the end. I prefer tea anyway.

Josh Greenslade is studying for a PhD at Imperial’s Astrophysics Centre

Sierra Nevada banner image by Geartooth Productions, article pictures Josh Greenslade.