Comet Lemmon is moving quickly west of the Big Dipper, near bright Arcturus, while Comet SWAN lies beneath the three stars that form the Summer Triangle. About 90 minutes after sunset is when to look for both.

A pair of once-in-a-lifetime comets are rocketing through our skies right now, and it's a rare treat because they won't be back for hundreds of years. The comets, C/2025 A6 (Lemmon) and C/2025 R2 (SWAN),

Astronomer Gianluca Masi captured spectacular footage of a glowing meteor trail wrapping around the colossal tail of Comet Lemmon on Oct. 24, as the wandering solar system body approached the constellation Serpens Caput in Earth's sky.

Lemmon, which is a rare green comet, can be seen with the naked eye on Oct. 21, according to the Royal Astronomical Society, with peak visibility near Halloween. SWAN may be visible using binoculars or a telescope, according to Starwalk, a real-time astronomical app for stargazing.

While NASA classifies the object as a harmless comet, per Economic Times, Loeb described the matter similar to a “blind date,” where he detailed: “You often assume that the dating partner would be very friendly, but you have to worry about serial killers, as well.”

The interstellar object 3I/ATLAS has gathered significant scientific attention, and soon it will reach its closest point to the sun.

Comet Lemmon was first discovered on Jan. 3, 2025, by the Mount Lemmon Survey near Tucson, Arizona, and will get closest to the sun on Nov. 8. Comet SWAN was only found on Sept. 11, 2025, as it looped around the sun.

Harvard Professor Avi Loeb discusses the mystery surrounding the 31/ATLAS comet and explains his argument that it has a 40% chance of being alien technology.

Comet C/2025 A6 (Lemmon) will pass through the neck of the great celestial serpent represented by the constellation Serpens Caput on the nights of Oct. 26-27.