APEX: The Atacama Pathfinder Experiment

Desert Eco-Lodge Alto Atacama 

The day starts early: too early for me. The reason? No, sadly not because of astronomy - rather, it is Adam
Donneky, the Director from In House Films who has a tendency to snore... quite loudly. Not helped by the plentiful and incredible Chilean red consumed the night previously - we enjoyed some superb hospitality at the desert lodge Hotel Alto Atacama. Wonderful fresh local ingredients like quinoa, chanar syrup, charquicán, purple potatoes, algarrobo... Amazing, and all with a backdrop of the desert and cliffs! However, after the snoring I am edging toward thoughts of torture - thankfully I resist the urge to dispense with Adam and turn my thoughts to
meeting researchers at APEX and discussing sub-millimetre
astronomy in depth.

The theory: all things emit radiation, even clouds of cold gas. APEX has superb resolution and can scan large areas of the sky quickly, looking for this radiation being emitted: cold regions of gas radiating energy. The intensity of the signal reveals how dense the emitting object is. These celestial objects could be a hydrogen-dense star-forming region or a proto-planetary disk, gravitationally attracting material as it forms a new planet.

Sub-millimetre astronomy is special! We look beyond the optical part of the light spectrum through which we "see" the Universe, investigating amongst other things, astrochemistry. The wavelengths are much longer and are often referred to as microwave radiation. One of the properties of microwave radiation is that it is readily absorbed by water. Microwave radiation excites water molecules and cause them to vibrate by transfer of energy, hmmm interesting, this is precisely why our microwave ovens are so successful at heating up food! Problem is: there is a lot of water in Earths' atmosphere, which absorbs the radiation before it can reach our telescopes.

The Chajnantor plateau in the shadow of APEX

Luckily, the higher you go up the less water there is... so this observatory is high: 5100 metres! It's spectacular, high on the Chajnantor plateau in Chile’s Atacama region. Set so high up, the telescopes here 'catch' the radiation from the Universe before it can be absorbed by moisture in the Earth's atmosphere, giving APEX a clear view into space. You can see some of what we experience in this video trailer from ESO!

Michael Dumke, Lead Astronomer at APEX

We arrive at the APEX control room and meet our host Michael Dumke, the lead astronomer at this incredible laboratory. APEX is the pre-cursor to ALMA with a 12m antenna concentrating in the sub-millimetre wavebands of light. The control facility is down in the valley floor, an ancient sea bed from prehistoric Earth. APEX sits in the bushes and shrubs and to me it feels like an eco holiday village in Atacama... quite different to some of the other ESO sites we've visited. I foolishly say this to Michael: oh dear! I'm forgiven though, and the tour continues to show me the seriousness of the research done here. Lots of interviews (you'll see these when the documentary is
released) and I also see a superb image of the
Horsehead Nebula stuck on the wall, in the sub
millimetre range... cooool (for a geek like me)!

The Horsehead Nebula in visible, infra red and microwave images (the final two)!

Now we head off to the antennae itself - to see first hand the APEX telescope! I am looking forward to

The APEX facility - spot the Moon!

getting up there - this is our second attempt as the first trip up to the 'high side' was foiled by a blizzard. Today however, the skies are beautifully clear! The 1 hour drive is spectaular, but very difficult because of the very low oxygen levels. We feel all sorts of strange physical effects: tiredness, sickness...

But on arrival we are met by Michael's staff and led into the control room which is oxygenated, ahh relief! After our briefing we head outside -  seeing the colour gradient in the blue of the sky was uniquely special. Smothered in UV 50 sunscreen we wander out to take pictures and conduct interviews.

Yes - it's a telescope!

Despite the sickness, the filming schedule and the pressure - I am in heaven. As we leave the facility, night starts to draw in and we stop to take pictures and film.The telescope, as you can see, is beautiful and we feel SO excited to be so close up!

As our conversations with Michael deepen it becomes apparent that just like a protoplanetary disk, we have 'accreted' another friend and plans are made for dinner that night in San Pedro de Atacama. Our group of 3 turns into 18...