Last Sunday, just after 4.30pm, I boarded an airliner in Christchurch. My destination wasn’t Dunedin, or some exotic holiday location. Instead, I was joining 12 expert astronomers, engineers, pilots and technicians on a 10-hour mission taking us thousands of kilometres south of New Zealand.
The airliner is a flying observatory called the Stratospheric Observatory for Infrared Astronomy (Sofia). A collaboration between Nasa and the German Space Agency, Sofia houses a 2.5m effective diameter telescope equipped with sensitive infrared detectors. Flying high in the stratosphere, Sofia is above most of the water vapour in Earth’s atmosphere which prevents IR radiation reaching the ground.
After a two-year absence due to the pandemic, Sofia is in Christchurch for a two-month deployment. The observatory is normally based in California. However, since 2014 she has visited Christchurch during southern hemisphere winter to observe objects invisible from her home base.
Sadly this is Sofia’s last visit to our part of the world. The observatory is being retired after over a decade of successful operation. The James Webb Space Telescope has capabilities far surpassing those of Sofia. Nasa has therefore decided that, from September, Sofia is surplus to requirements.
I was on board to set up a pair of camera platforms designed to photograph the Aurora Australis. Sofia regularly flies beneath the southern auroral oval on flights from Christchurch. After several years of effort, I persuaded Nasa to allow cameras on board.
As Sofia carried out her observations of distant galaxies, the cameras photographed the southern lights through windows behind the flight deck. Imagine my joy when the pilots asked if I would like to sit in the jump seat on the flight deck for our departure from Christchurch.
This week’s image shows the view I had as we reached cruising altitude. As darkness fell, the horizon was illuminated by a pastel glow caused by aerosols from the Tongan volcano which erupted in January.
Later in the flight, we had amazing views of the aurora. The Sofia experience was memorable on many levels. I will miss the visits of my favourite flying observatory once she has retired.
