When and Where to Spot Comet Lemmon
The best viewing window is about 90 minutes after sunset, lasting roughly 30 minutes. Observers should head to areas with minimal light pollution, such as Dark Sky Parks, for a clear view. Comet Lemmon will appear in the northwestern sky, moving west of the Big Dipper and near the bright star Arcturus.
For example, in New York City, where sunset occurs at 5:56 p.m. EDT, the ideal viewing time is 7:26-7:56 p.m. EDT. The 24%-lit waxing crescent moon will set early, providing darker conditions to spot the comet before its light is outshone, as per a report by Forbes.
Comet SWAN, meanwhile, will appear low in the southern sky, near the Summer Triangle stars and Saturn, and is visible with binoculars due to its faint glow.
How to Find Comet Lemmon
Observers can use binoculars sized 8×42 or 10×50 to locate the comet, which will look like a diffuse, fuzzy patch with a faint tail. Following the arc of the Big Dipper’s handle to Arcturus, then tracing a right angle toward Rasalhague in Ophiuchus, will guide stargazers to Lemmon’s location.
At the time of observation, Comet Lemmon will be approximately 56.9 million miles from the Sun and 59.8 million miles from Earth. Its position above the horizon varies by location, but from New York, it will be about 21 degrees high at 7:26 p.m. EDT, slowly descending as twilight deepens.
About Comet Lemmon and Comet SWAN
Comet Lemmon was discovered on January 3, 2025, by the Mount Lemmon Survey near Tucson, Arizona. It last visited the inner solar system in AD 875 and is not expected to return until around 3175, making this viewing opportunity once-in-a-lifetime for many stargazers.
Comet SWAN, found on September 11, 2025, has an orbit lasting approximately 20,000 years. While less bright than Lemmon, it offers a complementary spectacle for keen observers.
Comet Lemmon Viewing Tips
- Use stargazing apps such as Sky Guide, Stellarium, or SkySafari, or consult finder charts at In-The-Sky.com to pinpoint locations.
- Minimize light pollution for the clearest view. Avoid city lights and seek open spaces or high vantage points.
- Binoculars recommended; the comets appear as faint, diffuse patches with subtle tails.
FAQs
When is Comet Lemmon visible?
Comet Lemmon is best observed 90 minutes after sunset on Sunday, October 26, 2025, for roughly a 30-minute window.
How often does Comet Lemmon return?
It will not return for approximately 1,150 years, with its next expected visit around 3175 AD.
