A Night to Remember in the Sky
Get ready to look up — October 21 promises a breathtaking cosmic show. For the first time in over a millennium, Comet C/2025 A6 (Lemmon) will make its closest approach to Earth. At the same time, the Orionid meteor shower is expected to peak, sending dozens of shooting stars across the sky. These two events happening on the same night make October 21 a rare and unforgettable evening for stargazers.
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Comet Lemmon: A Green Visitor From the Depths
The comet, discovered in January 2025 by the Mount Lemmon Survey, has steadily brightened as it draws nearer to the Sun and Earth. On October 21, it will pass within about 0.60 astronomical units (AU) of us — a rare close approach.
What makes this comet visually striking is its green glow. This color arises from gases in its coma (primarily diatomic carbon, C₂) glowing under solar UV light — the same process that gives comets their characteristic hue. Estimates suggest it could reach a brightness that makes it visible to the naked eye under dark skies, though binoculars or a small telescope would enhance the experience.
In 2025, the comet will move through the constellation Boötes, appearing low on the northwestern horizon after sunset. Because of its long orbital period (estimated at 1,150–1,350 years), this may be the only chance for many of us to see it in our lifetimes.
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Orionids: A Shower From Halley’s Legacy
The Orionid meteor shower is a yearly display caused by Earth slicing through debris left by Halley’s Comet. These particles plunge into our atmosphere at high speed (about 66 km/s), burning up and leaving brilliant streaks across the sky.
In 2025, the Orionids are active from late September through early November, with their peak set for the late hours of October 20 into the early morning of October 21. What makes this year especially favorable is that the peak coincides with a new moon, meaning the skies will be darker and better suited for viewing faint meteors.
Under ideal dark-sky conditions, you might see 10–20 meteors per hour, with occasional bright “fireballs” and persistent glowing trails (“trains”) that light up the sky for several seconds.
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How to Catch the Show
Here are a few tips to maximize your chances:
Find a dark spot. Head away from city lights, toward a clear horizon with minimal light pollution.
Pick your timing.
– For the comet: shortly after sunset, when the western sky still holds light.
– For the meteors: the best viewing window is midnight to dawn, especially around 2 a.m. local time.
Look up and relax. You don’t need equipment — the wider your view, the better. Let your eyes adjust to the dark (about 20–30 minutes).
Bring the right gear. A reclining chair or blanket, warm clothes, a red flashlight, and some patience go a long way.
Use stargazing tools. Smartphone astronomy apps or a star-chart can help you locate stars and constellations to guide your gaze.
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What to Expect in One Night
On October 21, millions of kilometers overhead, a green comet will drift across the dusk sky, leaving a gentle tail behind it. Hours later, from past midnight onward, the Orionid meteors will blaze across that same dark canvas, each tiny streak telling a story from the trails of Halley. The combination comet and meteor shower in one night is rare, poetic, and thrilling. Keep your eyes on the sky, and you just might witness one of the most beautiful natural displays of the year.