Siding Spring Observatory Update
Published in the RSAA Lunations
Vol1 Issue63 1–30 June 2025
Distinguished Guests visit SSO
Siding Spring Observatory hosted a visit by both Her Excellency The Honourable Margaret Beazley AC KC, Governor of NSW and Distinguished Professor Genevieve Bell AO FAHA FTSE FASSA, Vice Chancellor of the ANU.
Brad Condon (SSO Site Manager) and Zoe Holcombe (RSAA) showed the VC the facilities at SSO, stopping by the 40” for a tour of the new accommodation.
Staff at the AAT (Zoe Holcombe, Chris Ramage, Jack Hon, and Gerard Hutchinson) showed our distinguished guests the AAT itself, providing explanations of how we aluminise the mirror, conduct observing, and how one of our primary instruments, 2dF, works. 2dF is over 20 years old and is currently undergoing a major refurbishment incorporating newer technology.
Following this, our distinguished guests enjoyed a reception at the SSO Lodge, followed by night sky viewing, led by Blake Estes (iTelescope).
Deep Space Optical Communications
The AAT has recently begun to be used for purposes other than astronomy. With observations of satellites (Sarah Caddy) and utilising the telescope and instruments for different purposes (Noelia Martinez Rey), the AAT has shown its utility and potential. During June, a team from Stromlo arrived to use it for a new purpose - deep space optical communications. The team utilised a near-infrared instrument deployed on an auxiliary port at the Cassegrain focus and additional equipment, including a Superconducting Nanowire Single Photon Detector, on the 4th floor to receive a human-made communication signal from 1.565 AU (or 234,120,667 km) away. Like most instrument deployments, there were a few hiccups, but also some fun as well. During the preparation process, the team tracked and observed several Solar System objects such as the asteroid Vesta and the Moon. With everything working as expected, the team were ready for their small window of opportunity to complete this deep space optical communication demonstration.
In between the testing period and the night of operations, the weather began to get more inclement, deciding it was a good time to snow at SSO for the first time in a few years (see the video of it snowing outside the lodge from Jamie Soon). On the night of operations, it was extremely cloudy, but there was a small window where the transmitting laser signal was able to be seen. Success! The AAT has received human-made photons from 1.565 AU away. And then, the clouds closed over again.
Whilst it would have been ideal if the weather had been better, it was a success for the team, demonstrating several outcomes, including utilising a communication instrument and existing F/8 instrumentation, such as Veloce, on the same night. In addition, a subset of the team was operating the Quantum Optical Ground Station at Stromlo and gathered additional data for this demonstration. This deep space optical communication demonstration was the first time that uplink/downlink optical communications have been completed across different continents.
This success would not have been possible without the enthusiastic support of everyone at SSO, with special thanks to Jack, Chris Ramage, Glen, Chappy, and Gayandhi at SSO, and to Elisa and Jamie at RSAA, for organising and getting it all up and running.
Gerard Hutchinson, Jamie Soon, Zoe Holcombe, Francis Bennet, Jack Hon, Gayandhi De Silva, and Chris Lidman, on behalf of the staff at SSO
Image: From left to right: Dennis Wilson, Jack Hon, Dr Gerard Hutchinson, Her Excellency The Honourable Margaret Beazley, Distinguished Professor Genevieve Bell, Chris Ramage and Zoe Holcombe. Photo by Blake Estes
