Spider eyes on the skies: Australia’s Huntsman Telescope

By Fred Watson, Australia's Astronomer-at-Large 16 November 2022
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The new Huntsman Telescope can see deep into the darkness where faint celestial structures hide.

What has eight eyes, eight legs, is brown or grey, and lurks in Aussie homes?

You’ve got it – a huntsman.

So, what has 10 eyes, one leg, is black, white and red, and stares at night skies?

I couldn’t resist that – it’s also a Huntsman.

In fact, it’s the Huntsman Telescope, a new telescope type that debuted this year at Australia’s national optical observatory at Siding Spring near Coonabarabran in New South Wales.

Operated by Macquarie University, it’s the brainchild of the university’s Dr Lee Spitler and is unique in the Southern Hemisphere, but was inspired by an instrument in the north.

The name comes from the telescope’s multiple eyes, which are actually large, high-performance telephoto lenses made by Canon and of a type usually used for the kind of wildlife photography seen in Australian Geographic.

These have remarkable freedom from scattered light, which makes them suitable for imaging faint astronomical objects. It means light from bright targets in the field of view doesn’t leak into an image’s darker parts, where very faint celestial structures may be located.

In a usual telescope with a single large mirror, those faint structures can be swamped by light scattered from brighter objects. So the Huntsman replaces the single mirror with 10 lenses, each with its own electronic camera, and these images can be added together electronically to create a single high-fidelity photo of the sky.

The Huntsman’s ability to deliver such clean images makes it perfect for particular investigations. For example, distant galaxies are often accompanied by faint light bands detached from the main structure of the galaxy. These are clouds of stars and usually symptomatic of some kind of disturbance in the galaxy’s history – a collision with a neighbouring galaxy, perhaps.

Investigating details of such past interactions requires the kind of images only the Huntsman can provide.

A final advantage of this remarkable telescope is it can grow. Unlike its arachnid namesake, which will never have more than eight eyes, the Huntsman Telescope can be fitted with more lenses, perhaps eventually doubling its sensitivity to the faint traces of celestial light that are its prey.

Related: First images from James Webb Space Telescope reveal distant galaxies in mind-blowing detail