An Alice Springs Experience, September 2019
It’s September 2019 and my pension pot has delivered again! This time, it is funding a visit to Australia, ticking off one of my final "big ticket" destinations. Visits to Sydney, the Barrier Reef and Darwin, for my favourite stopover in Kakadu National Park, had come and gone and I had enjoyed iconic sights, and great wildlife and landscapes, on a great holiday.
Astronomical sightings were not a priority for the visit and indeed the nature of the trip created some difficulties in pursuing them. Firstly, each evening was spent in a built-up area with the attendant light pollution. In most cases, the opportunity to travel into a dark area was limited (no car) but, where the opportunity did arise, a different problem appeared: wildlife. The known ability of a wide variety of Australian wildlife to ruin your day (or night) made me cautious to say the least. For sites near water, large yellow signs remind visitors of the constant presence of crocodiles, advising them to stay at least 10 m from the water's edge. Apparently, this distance should enable the unfortunate visitor to outrun a hungry crocodile, which will quickly give up the chase. In bush areas, a wide range of snakes, insects and even kangaroos present risk. Astronomical photography had to take place near to habitation!
The Ghan Railway took us on a four-day journey from Darwin across the centre of Australia to Adelaide. The first night’s stop at Katherine offered no opportunity to view the night sky. However, the second night’s stop at Alice Springs was different. Following a day touring the "sights" of Alice Springs, a town of some 30,000 souls, we were treated to "an outback pioneer dinner" at the historic telegraph station (1872) on the outskirts of the town. Quite what outback pioneers would have thought of our four-course BBQ dinner (which was excellent) is open to question.
The opportunity for photographing the night sky was decidedly mixed. The sky was diminished by arc-lights prettily illuminating the surrounding gum trees – yes, trees were also an issue. Undeterred I disappeared between courses behind buildings to hunt for some dark. Fortunately, and key to my photographic technique, there were a number of fence posts on which to balance the camera for an extended exposure time. My view from the shadows was indeed splendid, even with the leakage of light into the lower sky. The centre of the Milky Way was almost at the zenith; this was the first time that I had seen this region of the galaxy and it most certainly satisfied my needs for astronomical viewing during the trip. I set my Canon 100D with attached Tamron 18-200 mm lens to ISO 6400. I guessed infinity focus, positioned the camera pointing "straight up" then opened the shutter for around 20-30 s. As the evening progressed and I found darker places, I obtained some pleasing shots. Despite my limited memory of the central Milky Way, I could clearly identify the centre of the galaxy and the constellation Sagittarius with the Teapot asterism. Further bright patches suggested the location of the Lagoon and other nebulae. As an added bonus, I was fortunate to capture Jupiter in my photographs, beautifully framed below the centre of the galaxy.
On returning home, a little adjustment to brightness, colour balance and clarity produced the images below. I identified a small overlap with an image captured in April 2018 from New Zealand, and was able to align the images by the bright stars Rigel Kentaurus and Hadar (respectively α and β Centauri).
Camera settings for the following images: ISO 6400, exposure time 25-30 s, F/4.5 at 18 mm. In the composite image, the image taken from Australia is to the left and the one from new Zealand to the right.