This week at Mawson: 14 July 2023

Auroras and armpits go together like a horse and carriage.... Let me explain.

I have a new hobby; aurora photography. I knew there’d be good auroras down here, but it’s another level when you actually see them for real, stretching from horizon to horizon. I thought they were only green, but I’ve seen yellow, orange, and red and purple as well.

Like many people, I bought a good camera just before leaving Australia. I have an Olympus OM-D E-M10 Mark IV with a 14-150mm lens. It’s a good general-purpose camera, not specifically tailored for aurora photography. A wide-angle lens would’ve been better, but I’ve still managed to get a lot of shots I’m happy with.

It took me a few months to settle on camera settings, finding the balance between exposure, shutter speed and ISO. It changes depending on the sky, so you just have to keep trying out different combinations. It’s good to have a camera that you can set to take continuous shots. Auroras come and go, so leave it out for a few hours and review the (sometimes 100s of) shots later and pick the best ones.

A good phone camera is handy, too, and some shots are actually quite decent. Often, I’ll pop my head outside, take a few snaps with my phone, but by the time I’ve got the good camera setup, the aurora’s gone. And by pop outside, I mean put on thermals, jacket, beanie, gloves, boots and head torch.

This leads into what people back home don’t see in the photos, and that’s the effort involved in taking them. Walking in the dark in minus 25 degrees (with wind chill bringing that down to minus 35). Securing the tripod with rocks, wind gusts are unpredictable, and I learned the hard way after a cracked LCD screen.

It’s impossible to operate the camera with the big boofy AAD issue gloves, so you have to use just glove liners, whipping them out for a few seconds to setup then straight back in the gloves. Eventually, your hands will need to recover, and under the armpits are best for this, skin to skin for a fast heat transfer.

Batteries also don’t like the cold. Sometimes I can only get an hour’s use out of a full charge.

All this is good training for real work outside so that you know the limits of your clothing. You gain an appreciation of the good job it does protecting you. Your extremities are the first to feel the cold, so learning how to manage them is vital.

Andrew (Mawson CTO)

With the easing of winds and snow, we emerged from the blizzard that had delayed our departure on our first deep-field expedition of the season. The trip to Taylor Glacier, about 100km across the sea-ice to the west of Mawson, is undertaken each year just after mid-winter to coincide with the incubation period of the Emperor Penguins in the colony there. During this time, the males are huddled with their eggs awaiting the return of the females who have been out hunting through the middle of winter. This makes counting the number of breeding pairs significantly more straightforward, as only the males are in the colony. The trip also allows our Communication Technical Officers to service and download images from several automated cameras that watch the penguin colony year-round.

Six of the Mawson team, Dave, Nick, Allan, Alex, Alan, and myself, undertook the final preparation and loading of the green and blue Hägglunds vehicles. Ensuring all of our protective and safety equipment was in good order and, most importantly, we had enough good food and snacks to keep us energised for the planned four days in the field. Setting out from the station, the first stages of the trip went smoothly. The previous proving trip that had been conducted two weeks previously reassured us that the sea-ice was of sound condition through to at least Forbes Glacier. Unfortunately, due to the recent blizzard, the wind-swept snow had formed into patterns called sastrugi. These patterns, similar to sand dunes, can range from a few centimetres to a full metre in height. Due to these, our progress was considerably slower than expected and also placed extra stress on the vehicles (and our comfort) for the first five kilometres. Thankfully once we were amongst the Rookery Islands, the surface levelled out, and we picked up the pace.

Now making much better time, we again hit trouble off Forbes Glacier. One of the factors we must always be aware of when travelling on sea-ice is the dynamic nature of the surface. Currents, tides, and wind can cause large sheets of the ice to crack and move at any time. Since the proving trip, some such cracks had formed and were wide enough that we had to look for an alternative route to cross the crack at a safe crossing point. Another hour and a half was spent just getting through the five kilometres past the glacier before we were finally at the point that the proving trip had reached two weeks earlier.

From this point, we were in full exploration mode. Stopping every kilometre or whenever we found a crack, we measured the ice thickness to ensure it was completely safe to drive the Hägglunds on. Moving forward, parking into the wind, jumping out to measure, back into the vehicle (and warming ourselves), and repeat. The next ten kilometres passed relatively uneventfully as we were awestruck by the glacial ice and frozen-in-place icebergs around us. Such smooth going was unfortunately not to last. As we approached another crack, our measurement found that the ice beyond the crack was only 50cm - definitely not enough to proceed safely. From previous satellite photos, we know that this was a sliver of what had possibly been a polynya about three to four weeks before. A polynya is an open expanse of water surrounded by sea-ice. They are relatively common in Antarctica, but we knew that a particularly large one had been moving from west to east off the coast over the last month or so. With the sea-ice no longer thick enough, the day starting to lose light, and a large patch of sastrugi visible beyond the sliver of thin ice, we made the decision to return to station. Disappointed, the team took the chance to get some food in and take a few photos while the vehicles were checked over before heading back.

We will review the next few satellite photos to monitor the movement of the polynya and allow the sea-ice to thicken for a week or two before heading out again. We will get there!

Cat (Mawson Station Leader)