Later this month, two green comets are forecast to become visible — possibly to the naked eye — in an extremely rare double-act. The brightness of comets is famously difficult to predict, but these two are looking promising. In advance of that, comets Lemmon (C/2025 A6) and SWAN (C/2025 R2) can finally be observed by anyone in the Northern Hemisphere with binoculars or a small telescope, and patience. Here’s how to find them on Thursday, Oct. 9, 2025.
Comet Lemmon and Comet SWAN are the first comets visible in binoculars since Comet Tsuchinshan-ATLAS in October 2024. The brighter of the two, Lemmon, last looped around the sun about 1,350 years ago and will return around the year 3175. SWAN takes about 22,554 years to orbit the sun and will next visit in the year 24,579.
Comet Lemmon is visible before sunrise in the northeast, close to the Big Dipper, while Comet SWAN is low in the southwest after sunset. Patience is key, as is somewhere with dark western and northern horizons.
Both comets will appear as a small, diffuse patch that shifts night by night. Comet Lemmon is moving very quickly and will soon be visible in both the pre-dawn and post-sunset night sky.
Over the next two weeks, both comets will become more prominent, with their best showing expected at their closest approach around October 20–21, a date that coincides not only with a new moon but also the peak of the Orionid meteor shower.
On Thursday, Oct. 9, Comet Lemmon — discovered in January — will be visible in the northeast before dawn to the right side of the Big Dipper, low in the sky but trackable in binoculars. It will be about halfway between the stars Dubhe and Merak on the outside of the Big Dipper's bowl, and bright star Regulus.
The best time to look for Comet Lemmon will be a 30-minute window beginning about 90 minutes before sunrise where you are. For New York City, sunrise is 7:00 a.m. EDT, so the ideal viewing time will be 5:30-6:00 a.m. EDT (Venus will rise in the east during this time). The comet's height above the horizon will vary depending on your location, but from New York, it will be around 30 degrees up (about the width of the span of your hand, with fingers stretched out, held at arm's length) and rising. As well as fighting the increasing light of dawn, on Thursday, there's also the light of the 93%-lit waning gibbous moon, setting in the west, to contend with.
Blueish-green Comet SWAN — only discovered in September — will be visible in binoculars low in the southwest after sunset, to the right side of bright star Antares in the constellation Scorpius. It will be in line with the trio of bright stars that outline the head of Scorpius.
The best time to look for Comet SWAN will be a 30-minute window beginning about 90 minutes after sunset where you are. For New York City, sunset is 6:22 p.m. EDT, so the ideal viewing time will be 7:50-8:20 p.m. EDT. The comet's height above the horizon will vary depending on your location, but from New York, it will be around 12 degrees up (about the width of your fist held at arm's length) and sinking.
SWAN It will brighten and move higher into the sky during October as it moves northeastward into Scorpius and into Ophiuchus, then Serpens. It's expected to be at its best around Oct. 21, when it gets closest to the sun. It will then recede from Earth, dimming as it does.
Comet Lemmon and Comet SWAN are currently shining at mag. 5.8 and mag. 6, respectively, according to the Comet Observations Database, which puts them right on the cusp of naked-eye visibility — though very dark skies would be required. In practice, you'll need binoculars — preferably 10x50 or similar — or a small telescope. Outbursts or lulls can shift the apparent brightness quickly, so grab a view while you can.
To photograph a comet, you'll need to use either a smartphone or a manual mirrorless or DLSR camera. If mounted on a tripod or similar, a smartphone’s “night mode” or "pro mode" will take a long exposure and likely find the comet. If your smartphone has a RAW mode, use it. Using a DSLR camera on a tripod with a 50-105mm lens, begin with the following settings: ISO 800-1600, f/2.8–f/4 aperture, and a shutter speed of 2-5 seconds (set the focus to infinity or manually focus on a bright star or the moon using live-view magnification). In suburban skies, try slightly higher ISO and shorter exposures. You should pick up the comet's tails, even if you don't see them, using binoculars (which you should have with you to help you locate the comets).
Check my feed every day this month for a daily “comet tracker” with finder charts and tips for viewing Comet Lemmon and Comet SWAN.