Optical filters focus on the Sun

By Emily Lehmann

21 February 2020

3 minute read

machine orbiting the Sun

Solar Orbiter exploring the Sun’s realm. Credit NASA

Have you ever wanted to get up close and personal with the Sun? Well now you can, we have the technology! CSIRO scientists have designed optical filters that will reveal more about the Sun in all its glory. Our optical filters designed for space, blasted off last week onboard the European Space Agency and NASA’s Solar Orbiter.

New images of the Sun

Our scientists have developed a unique optical filter. It will allow astronomers to capture some of the most detailed images of our closest star. It will orbit the Sun at distances similar to Mercury. The Solar Orbiter with our optical filters onboard, will reveal the Sun’s innermost secrets. It will capture new images that feature extraordinarily fine detail – not seen before.

The mission is the first to provide multi-dimensional imagery of the star’s polar regions and inner heliosphere. These are the uncharted innermost regions of our Solar System. Lead scientist David Farrant said the optical filters are extremely accurate. They will allow the spacecraft’s instruments to take spectral measurements centred to within 1/30th of a nanometre. That’s one millionth the width of a single human hair!

Optical filters in space

The design of the optical filter allows it to withstand the forceful vibration of the launch. And also weather the Sun’s intense heat and high energy radiation. The filters are robust to survive the Solar Orbiter’s 10-year mission in space. Our optics lab is where we make these filters to such precise specifications for space travel.

We manufactured several filters and shipped them off to the Max Planck Institute. On arrival, they were assembled and tested, along with the rest of the spacecraft’s sophisticated equipment, to endure space travel. We developed a series of new techniques including precision laser measurements and a new testing chamber to produce these filters.

The Solar Orbiter’s images will offer unparalleled detail of the Sun’s magnetic and seismic activity. These images will provide new insights into sunspot activity, which will help in the prediction of solar winds and geomagnetic storms. This information can also make climate models here on Earth more accurate. In short, providing significant scientific, social and economic benefits.

gloved hand placing screw in optical filter

Our team designed and manufactured the optical filters which are now onboard the Solar Orbiter.

Revealing the mysteries

Before the Solar Orbiter mission, we developed a series of devices for the IMaX consortium, back in 2006. This included a stratospheric balloon-borne solar observation mission, travelling over the Arctic. It allowed our scientists to understand how this type of instrument responds to extreme conditions. This meant we could adjust specifications to suit.

Now that our team’s hard work has entered space, we’re excited to see what new insights and mysteries these images can unlock. We’ve developed high precision optics for some of the world’s most sophisticated observatories. And this is the first time we have actually sent our optics research out into our Solar System.

Now the team is focused on developing new optical systems for small satellites to monitor crops and water quality on Earth. This is part of our Space Technology Future Science Platform.