Comet Lemmon to light up the night sky as it crosses the path of a cosmic serpent — where and when to look

This weekend, if you step out, you'll be lucky enough to spot another star. Comet Lemmon, a faint green light with a soft tail, will be gliding near the Serpens constellation — a group of stars formerly called the “cosmic serpent.” It’s one of those moments where the sky feels alive again. The air is cooler, the evenings are longer, and a comet moving across the sky marks the change of season.

What makes Comet Lemmon special

Comet Lemmon — officially named C/2025 A6(Lemmon). This was first spotted at the Mount Lemmon Observatory in Arizona. It’s a typical comet in one sense, made of ice, dust, and old rock, but there’s nothing ordinary about the way it appears in the sky.

As sunlight hits its icy surface, the comet glows a misty shade of green and grows a trailing tail that looks almost alive. For a few weeks each year, this simple mix of light and dust becomes something extraordinary. This is something we can see with our own eyes from Earth.

When and where to spot it

The comet will be visible this weekend, substantially after 8 p.m., when the sky is dark and the Moon isn’t too bright. However, look low toward the western horizon if you’re in the Northern Hemisphere. Those in the Southern Hemisphere will get a better view — the comet will sit a little advanced in the night sky. 

Viewers really don't like a special outfit. On a clear night, down from megacity lights, it might appear as a faint, greenish smirch with a tail stretching behind it. A brace of binoculars or a small telescope can help bring it into focus, but indeed, with the naked eye, it’s worth the trouble. 

Find an open place, perhaps a rooftop, sundeck, or a quiet spot away from business. Let your eyes acclimate to the darkness for many twinkles before you start looking. The slower you search, the more likely you’ll see it. 

The “cosmic serpent” connection

This weekend, Comet Lemmon will drift through a region of stars called Serpens, Latin for “ snake. ” The constellation is divided into two. Serpens Caput( the head) and Serpens Cauda( the tail). Together, these two form a long, winding shape that actually looks like a serpent being held by another constellation called Ophiuchus, the serpent deliverer. 

As the comet passes by, its glowing trail will seem to weave through the serpent’s body.

How long will it stay visible

Comet Lemmon will remain visible for a few more weeks, but this weekend is when it’s at its brightest. After that, it will move farther from Earth and fade a little each night. If clouds get in the way now, you might still spot it later using a telescope.

There’s something calming about moments like these. A comet passing by doesn’t change our world, but it makes us pause. For a few minutes, we remember that we’re part of something much larger. A universe full of movement, beauty, and quiet stories unfolding above us.

So if the sky is clear tonight, step outside. Let your eyes wander. Somewhere near the serpent’s stars, Comet Lemmon will be moving gently through the dark — a soft green spark reminding us that the universe never truly sleeps.

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