On 12 December 2025 At 03:09:36 UTC, astronomers at the Armagh Observatory and Planetarium (AOP) have captured what is believed to be the first video recording of a lunar impact flash in Ireland, and the second recorded from the UK!
What you can see is a brief flash of light on the Moon’s night side, consistent with a small meteoroid striking the lunar surface. The event was captured using the Armagh Robotic Telescope (ART), located on site at the Armagh Observatory and Planetarium, by Andrew Marshall-Lee, a final-year PhD student at AOP.
Lunar impact flashes are rare events and are seen only very occasionally, although they are more likely to be detected during major meteor showers when the Moon passes through streams of debris left behind by comets and asteroids. This observation occurred during the peak of the Geminid meteor shower, making Geminids the most likely origin, though we’re still investigating it!
The objects responsible for these flashes are typically very small, often smaller than a golf ball, and are far too faint to be seen with a telescope while in space. When they strike the Moon at extremely high speeds, which in this case is estimated to have been around 35 km/s, their kinetic energy is rapidly converted into heat and light. This briefly vaporises material at the impact site and produces the flash seen from Earth.
Lunar impact flashes usually last only fractions of a second and are difficult to detect. However, it is possible for experienced observers using telescopes of around 20 cm aperture or larger to observe them, but doing so requires fast cameras, careful monitoring of the Moon’s dark side, and a great deal of patience.
We’ll be working hard to investigate all the details of the event but capturing this moment is a great achievement for AOP.
3 Comments
Kazzy · December 18, 2025 at 11:52
What a glorious capture! Our Moon is pock marked with so many impact sites; to see an actual hit is amazing.
Maurice · December 18, 2025 at 01:04
Is this flash similar to the Moon flashes that Sir Patrick Moore wrote about in his logbooks?
Heather Alexander · December 18, 2025 at 16:18
Hi Maurice, what Sir Patrick Moore logged was called Transient Lunar Phenomena which are mysterious, short-lived changes in the Moon’s appearance, like flashes, glows, or colour shifts, reported for centuries by astronomers and astronauts. These could be caused by meteorite impacts, gas releases (outgassing), or electrostatic effects. This is still a hotly debated topic. This Lunar Impact Flash is a confirmed strike on the Moon.