Comet Watch Tonight Spot Comets Lemmon and SWAN at Their Closest and Brightest
Stargazing enthusiasts have an exciting opportunity this week with the visibility of two comets: Comet C/2025 A6 (Lemmon) and Comet C/2025 R2 (SWAN). Both comets are shining brightly, making this an excellent time for skywatchers.
Visibility of Comets Lemmon and SWAN
On Tuesday, October 21, Comet Lemmon will reach its closest approach to Earth, approximately 56 million miles away. It is expected to shine at magnitude 4.5, comparable to the brightness of spring’s Beehive Cluster. Skywatchers may spot it with the naked eye in dark conditions, though binoculars are recommended for best viewing.
- Date of Closest Approach: October 21
- Brightness: Magnitude 4.5
- Distance from Earth: 56 million miles (89 million kilometers)
Comet SWAN Overview
Comet SWAN, which will come closest to Earth on Monday, October 20, is another captivating sight. It will be about 24 million miles away, significantly dimmer at magnitude 5.9. Observers will need binoculars to see this comet clearly.
- Date of Closest Approach: October 20
- Brightness: Magnitude 5.9
- Distance from Earth: 24 million miles (39 million kilometers)
Optimal Viewing Times
The best time to observe both comets will be approximately one and a half hours after sunset each evening this week. Here’s where to look:
- Comet Lemmon: Look northwest, near the Big Dipper and the bright star Arcturus.
- Comet SWAN: Find it in the southwestern sky, approximately halfway between the star Altair and the horizon, within the Summer Triangle.
Tools for Stargazing
To enhance your comet-watching experience, various resources are available. You can find sky maps and finder charts on platforms like The Sky Live and Stellarium. There are also apps such as Sky Guide, Sky Tonight, and SkySafari 7 Pro that can assist you.
Comet Orbits and Future Visibility
Comet Lemmon has a unique journey, completing its orbit around the Sun every 1,350 years. Jupiter’s influence has altered its trajectory, shortening its return period by nearly 200 years. Consequently, it won’t be visible again until the year 3179.
In contrast, Comet SWAN has a much longer orbital period of about 20,000 years, exiting the inner solar system this week. Its path takes it farther from Earth, making it less bright during this appearance.
Conclusion
Whether you’re a seasoned astronomer or a casual observer, this week presents a rare chance to witness two stunning comets. Grab your binoculars and look to the skies for Comets Lemmon and SWAN at their closest and brightest!
