Dual Green Comets Are Going To Streak The October Skies, How To Watch

Stargazers, here's a new one to add to your October view list. Two newly discovered comets, both sporting vibrant green hues, are set to grace the night sky, AND if the conditions are right, there's also a rare naked-eye opportunity to view the comets alongside the peak of the Orionid meteor shower at the end of the month.

The comets in question are Comet C/2025 A6 (Lemmon) and Comet C/2025 R2 (SWAN). While comets are famously unpredictable, current forecasts suggest Comet Lemmon could be the most stunning. Discovered earlier this year, it has been rapidly brightening and is anticipated to reach a magnitude as low as +3.5 to +2.5, i.e. at a brightness level that makes it visible to the unaided eye from dark-sky locations. It's expected to pass closest to Earth on October 21, conveniently transitioning into the evening sky (for Northern Hemisphere folks) by mid-month, making it an ideal target low on the northwestern horizon after sunset.

Comet SWAN could also turn out to be interesting. Although expected to be slightly dimmer, hovering around magnitude +6, it should still be an easy catch with binoculars. It makes its closest approach just a day before Lemmon (October 20) appearing low in the southwestern sky after dusk.

This viewing culminates around October 21, coinciding with two major astronomical events. First, the new moon provides the darkest possible sky conditions, which, guess what, is perfect for spotting faint, fuzzy objects like comets. Second, the Orionid meteor shower also reaches its peak on the night of October 20-21. Just imagine streaking comets against the backdrop of this annual shower (that can offer up to 20 meteors per hour)—that'll make for some great memories and photos!

For those interested in checking these out (thanks to StarWalk for the tip), look to the northwest after sunset for Comet Lemmon, which will be traversing constellations like Ursa Major and Boötes. For an easier find, look near the bright star Cor Caroli in Canes Venatici around October 16. Comet SWAN will be visible low on the southwestern horizon. Astronomers advise using a decent pair of binoculars for the best view, as a comet's light is diffused over a wider area than a star, making it harder to spot with the naked eye even at a bright magnitude.