At first I couldn’t make sense of the clumsy, dark shape against the sky, but as we drew nearer, I realised it was a soldier manning a roadblock. The bus hissed to a stop, and the soldier paused only to spit out his gum before swinging on board. A fine dust shrouded his uniform and face as he walked down the aisle of the bus towards me.

My colleagues had warned me about the roadblocks. But the woman sitting next to me carried on eating her sandwich, and the soldier didn’t even look at me as he shuffled through my passport, before dropping it back in my lap. I felt obscurely insulted. As the bus pulled away and started to wheeze up the highway, the woman silently handed me an apple.

That was on my first trip. Since then I’ve learnt that most people here don’t talk about politics. They swerve around it, as if avoiding a dead animal on the road. In any case, at that time in Chile, a soldier stopping a bus was part of the daily routine and not worth commenting on.

The woman’s apple sat on my desk at the observatory all through my trip. I only threw it away at the end. I liked looking at it, but it seemed too red and perfect to be edible.

Now when I come here, there are no more roadblocks, and the journey is a lot quicker. Speeding down the highway, I can spot the bright shiny telescope domes high in the mountains. There’s nothing else to look at; before the observatory was built forty years ago by Europeans, this place didn’t exist. The nearest town is over a hundred kilometres away. That’s what makes it such an ideal place to do astronomy; there are no distractions. Nothing gets in our way here.

This trip, I’ve got a new telescope operator. I’m able to tell him where I want him to point the telescope, but that’s about the limit of my Spanish. We sit in the small control room off the side of the telescope dome, and eat biscuits all night without speaking very much.

On this first night of a two-week stint, I go into the dome itself to check that the telescope is set up properly. The dome curves about me as if I’m at the centre of all this darkening space, and above me the dumb bulk of the telescope waits for its instructions. I stand in the dark and breathe the desert air.

The telescope operator spends a lot of time reading a newspaper. I can’t remember his name so I have to cough to get his attention every time I want him to do something. But we manage to establish a routine; type in the galaxy’s coordinates, lock the telescope onto it for ten minutes, then read out the resulting image, store it on the computer, and start again with the next galaxy.

The night settles down into ten minute cycles, and here in the almost cosy greyness of the control room, with its shelves of computer tapes and astronomy books insulating the walls, sometimes I forget that the outside exists. Over the years of long nights that I’ve spent at telescopes, I’ve learnt that it’s easy to shrink your universe down to your surroundings.

But tonight, even though we get our routine going, there’s something not quite right. I can’t figure it out at first. The room is quiet, all I can hear are the newspaper rustling and the distant hum of the telescope motor. Everything should be peaceful. Then I realise that each time we start a new observation, the telescope operator picks up his newspaper and I get a glimpse of the photo on the front page. This photo shows some long bundles of cloth lying on the ground somewhere, with people standing around them, looking at the camera. It feels like they’re looking directly at me. Their faces are serious, even accusing, although I don’t understand what it is they’re accusing me of. I can’t make any sense of it, there’s not enough information, so I look away.

Then the telescope finishes its observation and the next image is displayed on the screen. It’s a good one; the galaxy is nicely defined. Both its bright centre and faint spiral arms are clearly visible. You can discover a lot about a galaxy’s history from its appearance. Some of them get incredibly distorted by gravitational forces and interactions, two galaxies can rip each other apart if they get close enough.

I tell the telescope operator to acquire the next target and we carry on. From time to time I think how odd it is that I should be the first person to see these galaxies; it feels like an unveiling. But there are no fanfares here. We eat a lot more biscuits.

The next afternoon I’m sitting in the canteen eating lunch, when Don appears. He sits down opposite me with his little cup of treacly coffee, and stirs sugar into it, unsettling the dark surface. There’s something different in his face. Back home he always looks sleepy, only half-bothered by what’s going on around him. But here his eyes are alert and more open. I wonder if I look different, too.

“Heard about the bodies?” He asks me.

Bodies? I remember the huddles of cloth in the photo, “I saw something in the newspaper. I don’t know – ”

“Yeah, that’ll be them. They were found at Chacabuco. Christ, that’s not far from here.”

I’ve never heard of Chacabuco, I only know the road between Santiago and the observatory. I concentrate on trying to get the peel off my orange in one long spiral, trying not to think of bodies hidden in the desert around us.

If you glance out of the window while you’re eating your lunch, you’d think humans had never been here. All you can see are mountains and blue sky, like a painted backdrop.

“What are you doing on the telescope?” he asks.

“I’m part of that big galaxy survey. We’re imaging every single galaxy in the Southern sky out to a redshift of 0.2.” Even though I’ve been working on this project for years, I still feel pride at our achievements. Every single galaxy. It’s like cataloguing fish in the sea, or pebbles on the beach.

He picks up my spiral of orange peel, but it breaks in his fingers, “Aren’t the galaxies looking more disturbed than you predicted? Do you know why that is?”

I don’t know; I’m not working on that aspect of the data. Don has a knack of asking me questions I can’t answer. He continues, “Still, it’s a good piece of work. Thorough.”

I am thorough. I’m good at my job; I can image and process more than sixty galaxies each night.

He rubs the peel, releasing the smell of the orange into the sterile air around us. “Mmm,” he says. “How long will it take to finish the survey?”

“Forty-eight more nights.”

“That’s very precise.” He smiles at me, and I wonder if he is mocking me. You have to be precise for this work. I don’t see the humour in what I have said and I don’t want to wait for any more of Don’s questions, so I decide to go outside and get some fresh air before night falls.

I wander down to the stone circle. I do this every time I come here. There’s always a point at which I get fed up with the telescopes, and I need to look at something older that isn’t shinily perfect. I don’t know when the circle was created but it must be very old. The lumps of rock are almost sunk into the ground and it’s difficult to make it out from the surroundings. But I’ve been here many times before. I like to think that the people who built it would have been star-gazers, anyone living under this sky would have stared at it night after night, told stories about the constellations, made it part of their culture. It’s comforting to feel a link with these people. I sit down on the edge of the circle, and I shut my eyes.

I’m awoken by the sound of barking. The blue has faded from the sky; it’s already sunset. I’ve been out here far too long. I should be at the telescope, preparing for the night. I try to stand up but then something hurtles at me and knocks me over onto my back. It’s a wild dog. You sometimes see them at lower altitudes, but never this high up. The dog stands over me, its damp breath in my face feels warm and horribly intimate.

I’m too scared to shout. I try moving my arm slowly but it snaps its teeth and so I have to lie still, just watching it. There’s a thick layer of dust on its fur, the same colour as the sandy rocks. It could have crawled out of this landscape; it would be invisible from fifty metres away.

“Nice dog,” I mutter and it growls. I’m close enough to note the utter blankness of its eyes. The sky is rapidly growing darker and I have to move. I can’t be out here at night, I’d never find my way back to the observatory. Panic makes me shove the dog and it springs away, kicking me in the ribs as it does so, before disappearing into the rocks. Winded, I stagger back up the path, my shadow creeping ahead of me.

That night I can’t seem to communicate properly with the telescope operator. The weather is clear and the images are as sharp as they could be, but he’s slow, taking an age to acquire each galaxy. I’m frustrated, I hate wasting time. At one point he’s reading his newspaper when he should be working, so I cough loudly but he still doesn’t move.

The door opens and Don walks in. I wonder why he isn’t working. I open my mouth to tell him about the dog but, to my astonishment, he goes straight over to the telescope operator.

“I’m sorry,” he says.

The operator smiles and takes his outstretched hand. They stay like that for some time, their hands clasped together.

“What’s going on?” I ask.

Don turns to me, “The bodies at Chacabuco. One of them is his uncle.”

I stare at the telescope operator, “Your uncle?”

Don carries on, “People were sent to the concentration camp at Chacabuco when they challenged the regime, and they disappeared. Their bodies have only just been found.”

I walk over to the newspaper. But, as before, the photo offers little information. I hope whatever’s wrapped up in the cloth is protected from the dogs.

Don says, “He was a good man. He did what he could.”

Above us the telescope continues to whirr, a steady comforting sound. I wonder if the people at the concentration camp could see it. Did they hope that it would discover them? But you can’t point a telescope at the ground; it would buckle under its own weight.

I want to say something to the telescope operator, but I can’t think what. The telescope finishes its observation, and yet another image of a galaxy appears on the screen, as sharp and crisp as ever. We all stare at it in silence.