Comet 3I/ATLAS reaches its closest point to Earth tonight: How to see it in the sky and online
Comet 3I/ATLASThe third interstellar object ever detected by astronomers, will make its closest approach to Earth on Thursday night (December 18 and 19), when it will arrive just 168 million miles (270 million kilometers) from our planet. This poses no threat to Earth.
The precise moment will come at 1:00 a.m. EST (06:00 GMT) on December 19, according to Espace.com. Although it is still a little less than twice Earth’s distance from the sun – which will prevent great photos with giant telescopes – it is a unique opportunity to glimpse an object from another star system. Discovered in July 2025, it follows 1I/’Oumuamua in 2017 and 2I/Borisov in 2019.
Any planetarium app – such as Sky Tonight, Sky Guide, Stellarium and SkySafari 7 Pro – will also have 3I/ATLAS in its database. This will be useful for finding it visually. Technically, it’s visible in large astronomy binoculars, but at magnitude 11 it will look “like a small, slightly fuzzy star,” according to Sky at night.
A better way to observe the comet is with a medium to large telescope of around 12 inches, according to NASAthrough which observers can spot a faint blur of greenish light near the bright star Regulus in Leo and a fainter companion, called Rho Leonis.
In the meantime, astronomical telescopes on Earth and in space will continue to monitor it, some at distances much closer than we will get. Just today, NASA released new ultraviolet images of the comet taken with its Europa Clipper spacecraft about 102 million miles (164 million km), reducing the distance from Earth by about a third. Stay tuned for more image releases from NASA after the close approach.
