Comet C/2025 A6 Lemmon
Chart of Comet Lemmon location Hawaii
Approximate Sunset Viewing Details for HAWAII
Time: About 30 to 60 minutes after sunset is likely your best window when the comet is highest above the horizon (before it dips down into twilight).
Direction: Look toward the western to northwestern horizon.
Altitude: The comet will not be very high above the horizon—only a few tens of degrees (depending on how far into October you go).
Nearby stars/constellations to use as guides:
In early‑mid October, the comet is still near Ursa Major / the Big Dipper region.
Later in October, it moves toward Canes Venatici, then into Boötes.
10,000 feet on Haleakalā is one of the best places on Earth to view Comet Lemmon — seriously.
At that altitude:
You’ll be above most of the atmosphere, clouds, and light pollution.
Skies will be exceptionally dark and steady, especially on moonless nights.
Your western and northwestern horizon will be clear, especially from the summit overlook.
Final Tips for Viewing Comet Lemmon from Haleakalā
🔭 When
Best window: ~30–90 minutes after sunset.
Around Oct 12–21, the comet will be near peak brightness and visible in the northwest sky.
🧭 Where to look
Face WNW to NW about 45 minutes after sunset.
The comet will be low in that part of the sky, climbing slightly each night.
Look near Ursa Major and Canes Venatici — binoculars will help locate it if it's still faint.
📱 Tools
Use SkySafari, Sky Guide, Stellarium, or Star Walk 2 with location set to Haleakalā.
Search for "C/2025 A6 (Lemmon)" and activate the augmented reality (AR) mode to match the sky view.
🌒 Moon phase tip
Try to go before full Moon (Oct 13 is first quarter), to avoid bright moonlight washing out the view.
Darker skies = better comet visibility.
Tail behavior:
The comet is expected to produce a significant tail. Some simulations and observations suggest dramatic changes, like “tail disconnection events” (where solar wind or magnetic activity strips part of the tail) have already been seen.
Tail length in deep exposures could reach 20° to 50° under favorable conditions (very dark skies, strong activity) according to some predictions and simulations.
Color / composition:
Like many comets, it may show a greenish hue, primarily from gas emissions (diatomic carbon, C₂) in its coma being excited by sunlight.
Uncertainty: As with all comets, brightness is notoriously hard to predict. The coma, tail, and how much volatile material is released can vary. Even if models suggest a naked-eye magnitude, real-world conditions (light pollution, moonlight, atmospheric conditions) may limit visibility.
Why is Comet Lemmon moving fast? 130,000 MPH
High velocity: Comets coming from the outer solar system (like the Oort Cloud) tend to travel very fast as they approach the Sun because of the Sun’s strong gravity pulling them in.
Parabolic or hyperbolic orbit: Many new comets have orbits that are highly elongated (almost parabolic or even hyperbolic), meaning they swing in close to the Sun once and then speed back out into deep space, often never to return.
For Lemmon, its velocity relative to the Sun is on the order of tens of kilometers per second—fast enough to cover large distances quickly.
What does that mean for us?
Short viewing window: Because it’s moving so fast, the comet’s position changes noticeably from night to night, so you’ll want to catch it during its peak brightness period (mid-October).
Rapid changes: Its brightness and tail structure can change quickly as it nears perihelion (closest point to the Sun) and then moves away.
One-time visitor? Many of these comets are on trajectories that mean they’re just passing through the inner solar system once before being flung back out into space.
So yeah, Lemmon is like a fast-moving interstellar visitor putting on a show for us before speeding off into the cosmic night!
CoMET Trivia
Comets are cosmic snowballs — made of ice, dust, and rock, leftover building blocks from the solar system’s formation about 4.6 billion years ago.
Two types of comets:
Short-period comets orbit the Sun in less than 200 years (like Halley’s Comet, every 76 years).
Long-period comets take thousands or even millions of years to complete an orbit, coming from the distant Oort Cloud.
Comet tails always point away from the Sun due to the solar wind pushing dust and gas outward, no matter which direction the comet is moving.
The word “comet” comes from the Greek ‘komētēs,’ meaning “long-haired,” because ancient astronomers saw their glowing tails as flowing hair.
Halley’s Comet is the only short-period comet visible from Earth with the naked eye that visits regularly, last seen in 1986 and returning in 2061.
Comets can surprise us — some brighten dramatically and become spectacular “Great Comets,” while others stay faint and elusive.
Rosetta mission (2014-2016) was the first to orbit and land a probe (Philae) on a comet (67P/Churyumov-Gerasimenko), revealing incredible details about comet composition.
More Comet Fun & Stories
The Great Comet of 1680 (Kirch’s Comet)
The first comet discovered by telescope! It was spectacularly bright and visible even in daytime for a short while. It sparked lots of excitement and debate about comet orbits.
Comet Hale-Bopp (1997)
One of the brightest comets of the 20th century, visible for over a year to the naked eye.
It had two distinct tails—a dust tail and an ion tail—and inspired a surge of public interest in astronomy.
Comet Shoemaker-Levy 9 (1994)
This comet famously crashed into Jupiter, providing the first direct observation of a collision between two solar system bodies.
The impacts created massive scars on Jupiter visible for months.
Tails with different colors!
The dust tail shines white or yellowish by reflecting sunlight.
The ion tail can glow blue or green due to ionized gases like carbon monoxide.
Comets can have “jets” — localized eruptions of gas and dust caused by sunlight heating parts of the nucleus, making the comet’s surface active and dynamic.
Comet nuclei are surprisingly dark — they reflect only about 4% of sunlight, roughly as dark as coal. So a bright comet is really shining because of its tail and coma, not the nucleus itself.
Some meteor showers come from comets — like the Perseids from Comet Swift-Tuttle and the Leonids from Comet Tempel-Tuttle. When Earth passes through their debris trail, we get “shooting stars.”