How we sharpened the James Webb telescope's vision from a million kilometers away

En route to its deployment, Webb had to successfully navigate 344 potential points of failure. Thankfully, the launch went better than expected, and we could finally breathe again.

Six months later, Webb's first images were revealed, of the most distant galaxies yet seen. However, for our team in Australia, the work was only beginning.

We would be using Webb's highest-resolution mode, called the aperture masking interferometer or AMI for short. It's a tiny piece of precisely machined metal that slots into one of the telescope's cameras, enhancing its resolution.

Our results on painstakingly testing and enhancing AMI are now released on the open-access archive arXiv in a pair of papers. We can finally present its first successful observations of stars, planets, moons and even black hole jets.

A 'selfie' taken during Webb's testing on Earth. Credit: Ball Aerospace

The primary mirror of the Webb telescope consists of 18 precisely ground hexagonal segments. Credit: NASA/Chris Gunn

AMI allows for a precise test pattern that can help correct any issues with JWST’s focus. Credit: Anand Sivaramakrishnan/STScI

A map of the HD 206893 system. The colorful spots show the likelihood of there being an object at that position, while B and C show the known positions of the companion planets. The wider blob means the position of C is less precisely measured, as it’s much fainter than B. This is simplified from the full version presented in the paper. Credit: Desdoigts et al, arXiv (2025). DOI: 10.48550/arxiv.2510.09806

Jupiter’s moon Io, seen by AMI on Webb. Four bright spots are visible; they are volcanoes, exactly where expected, and rotate with Io over the hour-long timelapse. Credit: Max Charles