As the number of satellites around Earth grows, astronomers increasingly need ways to predict and avoid these crossings.
Why satellites are a problem for astronomyImage from Blanco 4-meter telescope at the Cerro Tololo Inter-American Observatory (CTIO).
The European Space Agency estimated in June 2026 that roughly 18,340 satellites remained in orbit, including about 16,000 still functioning.
These satellites can streak through telescope images, emit disruptive radio waves, and collectively create a form of global light pollution.
Closing a camera shutter would do nothing to protect radio telescopes from satellite transmissions or unintended electromagnetic emissions.
Artistic depiction of the solution scientists are proposing for solving satellite glare during astronomical observations.
A telescope can spend hours collecting the faint light of a distant galaxy. A fast-moving satellite needs only a few seconds to cross its field of view, leaving a bright streak that contaminates (and sometimes ruins) the long exposure.
As the number of satellites around Earth grows, astronomers increasingly need ways to predict and avoid these crossings. Researchers at the University of Warwick are now developing an early-warning system that could spot an approaching satellite and alert a telescope before it enters the image.
The system uses a neuromorphic camera, a novel type of sensor inspired by the way biological retinas respond to changing light. Positioned beside an astronomical telescope, it would monitor a broad area of sky and give the observatory several seconds to close its shutter, delay an exposure or switch to another target automatically.
In other words, the telescope could blink at precisely the right moment.
Why satellites are a problem for astronomy
Image from Blanco 4-meter telescope at the Cerro Tololo Inter-American Observatory (CTIO). Image containes at least 19 streaks created by the second batch of Starlink satellites. Image credits: NOIRLab.
Satellites are incredibly useful. They provide internet connections, GPS, weather forecasts, and offer a wide array of information about our changing planet. But large constellations have also transformed the environment some astronomers are working in.
The European Space Agency estimated in June 2026 that roughly 18,340 satellites remained in orbit, including about 16,000 still functioning. Many travel through low Earth orbit, where they can move rapidly across an observer’s sky.
“The trouble is that as more and more is launching, we’re struggling to keep up with the space traffic management that’s required to keep up with all these new objects,” said James Blake, a space researcher at Warwick, who presented the system on July 21 at the UK’s National Astronomy Meeting 2026 (NAM2026).
These satellites can streak through telescope images, emit disruptive radio waves, and collectively create a form of global light pollution. The scale of this problem is now too great to be ignored and every new satellite only makes things worse. At almost any major astronomy conference, you’ll hear stories about a bright streak crossing an exposure—or about the growing effort needed to predict, mask, and work around them.
“You can see Starlink everywhere. It’s a problem across the whole of the electromagnetic spectrum,” said Mike Peel, postdoctoral researcher at Imperial College London, at NAM2026. Wide-field surveys are especially vulnerable because they photograph large areas of sky repeatedly.
A satellite doesn’t even need to use its own light to interfere with astronomy. While the ground below is dark, sunlight at an angle can still strike the spacecraft and reflect toward a telescope.
“It’s going to damage your data. It’s going to damage the scientific output of your experiments,” Blake added.
Astronomers have tried to push several forms of mitigation. For starters, they’re pushing to make satellites less reflective, but without any legislation in place, companies are often ignoring this push. Scientists are also asking for information on when and where satellites are passing, but the accuracy of this data is not fully reliable and can be disrupted by spacecraft maneuvers.
So instead, Blake is looking for a different approach.
A camera that watches for change
A conventional digital camera records complete frames at regular intervals. Even when almost everything in the scene remains still, it repeatedly measures and transmits information from every pixel.
A neuromorphic, or event-based, camera works differently. It’s inspired by the way biological retinas respond to visual changes, its pixels report increases or decreases in brightness as they happen, Blake explained.
A star that remains steady produces little new information. A satellite moving across the sky triggers a rapid sequence of events along its path.
“Every pixel, if it doesn’t detect a change, it’s going to stay silent,” Blake said.
A steady star therefore produces relatively little new information. A satellite moving through the scene generates a rapid chain of events along its path.
This approach can avoid recording large amounts of redundant information while providing extremely precise timing. Event-based cameras also cope well with fast movement and a wide range of brightness levels, qualities that have already attracted interest from researchers tracking satellites, meteors and orbital debris. Warwick system would use the neuromorphic camera as a sentry. It would watch a larger patch of sky than the main scientific instrument, identify moving objects and calculate whether their trajectories are likely to intersect the telescope’s field of view.
“We have a responsive system, whereby in near real time you’re acting on what you’re seeing in the night sky rather than relying on old information,” Blake said at NAM2026.
An initial timing analysis presented at NAM2026 suggested that detecting a satellite several degrees outside the protected field could leave only several seconds for the software and telescope to respond.
That may not sound like much, but it could be enough for an automated system to save the precious exposure from light contamination. Telescope time is very expensive, and every trick helps and adds up.
The telescope might briefly close its shutter and reopen it after the satellite passes. It could postpone the start of an exposure or move to another target in its observing schedule. The spacecraft would still cross the sky, but its trail might never reach the scientific image.
What this can and can’t do
Comparison of the data produced by an event camera and a conventional camera. Image via Wiki Commons.
This approach won’t help every observation. If astronomers need a precisely timed measurement or an attempt to capture a brief cosmic event, you can’t just pause the observation while a satellite passes. Plus, some instruments may not be able to interrupt an exposure cleanly. The system must also distinguish satellites from aircraft, meteors, detector noise and other changing sources. It then has to calculate a reliable trajectory quickly enough to make the warning useful.
The method would also address only optical contamination. Closing a camera shutter would do nothing to protect radio telescopes from satellite transmissions or unintended electromagnetic emissions.
But if it works, it could solve one of the most immediate practical problems facing observatories: how to protect a long exposure from an object that crosses the field in seconds. Instead of discovering the streak after the data have been collected, astronomers could briefly close the shutter, delay the exposure or move to another target. The telescope would, in effect, blink at the right moment.
The work forms part of Warwick’s Preserving Dark Skies with Neuromorphic Camera Technology project. The researchers plan to commission a prototype at Warwick’s campus observatory and later use facilities on La Palma in the Canary Islands.
“We’re hoping to take that out and test that on sky very soon in the next couple of weeks, hopefully,” Blake said at NAM2026.
