The fourth LaserSETI site is now active on Isla Magueyes, off the southern coast, hosted by the University of Puerto Rico (UPR) at Mayagüez’s Department of Marine Sciences. It includes three wide-field optical instruments, each pointing in a different direction to maximise sky coverage.
With this addition, LaserSETI has boosted its coverage from around one-third of the night sky to nearly 40 per cent, taking another substantial leap towards its goal of “all-sky, all-the-time” monitoring.
The technology is unlike traditional telescopes. Instead of observing narrow slices of sky, LaserSETI uses pairs of wide-field cameras to continuously monitor large regions for very brief (millisecond) monochromatic light flashes, which could indicate technosignatures – signs of advanced civilisations.
Local involvement is central. Students from UPR-Mayagüez will help maintain the equipment and assist in data analysis, including studies beyond SETI, like meteor observation.
Strategically, Puerto Rico fills a geographical gap. Its southern skies offer clearer conditions and reduced light pollution compared with parts of northern Puerto Rico. Overlaps in field of view with existing observatories in Arizona and future plans in the Canary Islands will help confirm possible signals by cross-checking.
The SETI Institute says this expansion strengthens the network’s ability to detect fleeting optical phenomena anywhere in the sky at any time.
LaserSETI is the first project aiming to provide continuous, all-sky coverage in the search for extraterrestrial intelligence. Its instruments are purpose-built to detect laser pulses originating beyond our solar system and are being deployed as a coordinated network across a dozen strategically selected observatories worldwide.
Each unit consists of two wide-field, high-sensitivity cameras paired with a transmission grating, which splits incoming light into its component colours much like a prism. The cameras use a modified CCD readout method known as time delay integration. This technique deliberately smears images along one axis but enables millisecond-level time resolution.
The twin cameras are aligned in the same direction but set at right angles to one another. This arrangement allows events to be pinpointed in both axes while also providing an extra layer of confidence in verifying detections.