How a multi-lens telescope enables daytime astronomy observations

In a paper published in Publications of the Astronomical Society of Australia today, astronomers at Macquarie University have successfully tested a new technique for observing celestial objects during the day using the Huntsman Telescope.

This unique array of 10 camera lenses, originally designed for ultra-sensitive night sky observations, can accurately measure stars, satellites, and other targets even when the Sun is high overhead.

The research team used special 'broad band' filters on a test version of the telescope to block most daylight while allowing specific wavelengths from celestial objects to pass.

“People have tried observing stars and satellites in optical wavelengths during the day for centuries, but it has been very difficult to do. But our tests show Huntsman can achieve remarkable results in daylight hours,” says lead author, astrophysics PhD candidate Sarah Caddy, who helped design and build the Huntsman Telescope.

The Huntsman's daytime capability allows continual monitoring of bright stars like the red supergiant Betelgeuse, which can be unobservable at night for months at a time when its position is close to the Sun.

Betelgeuse dimmed substantially from late 2019 through 2020, likely due to a major ejection of gas and dust.

“Without this daytime mode, we'd have no idea if one of the brightest stars in the sky has gone supernova until a few months after its explosive light reached Earth,” says co-author Associate Professor Lee Spitler, Head of Space Projects at Macquarie's Australian Astronomical Optics (AAO).

The study also has significance in the rapidly expanding field of space situational awareness (SSA), the close monitoring of the ever-growing population of satellites, space debris and other artificial objects orbiting Earth.

With plans launch a further 50,000 low Earth orbit satellites in the next decade, there’s a pressing need for dedicated day and night telescope networks to continually detect and track satellites and visually check their composition, age and condition.

“Opening up to daytime observation of satellites allows us to monitor not just where they are, but also their orientation, and adds to the information we get from radar and other monitoring methods, protecting against potential collisions,” Ms Caddy says.

“Being able to do accurate, round-the-clock observations shatters longstanding restrictions on when astronomers can scan the heavens,” says Associate Professor Spitler.

“Daytime astronomy will be increasingly critical as we enter the next Space Age.”

Canon Australia provided support for this project, and with the Huntsman Telescope collaboration.

Read more at The Lighthouse:
https://lighthouse.mq.edu.au/article/may-2024/stargazing-in-broad-daylight-how-a-multi-lens-telescope-is-changing-astronomy