This autumn, two greenish comets are traversing the inner solar system, presenting a unique opportunity to view them in the coming weeks.

The comets, designated C/2025 A6 (Lemon) and C/2025 R2 (SWAN), are currently observable from the Northern Hemisphere as they journey through our cosmic vicinity.

It is quite uncommon for a comet to be visible twice within the same month.

Both comets can be observed with binoculars or small telescopes until the end of October. Comet Lemon may become visible to the naked eye around its closest approach to Earth and peak brightness on or about October 21st.

Several astronomy enthusiasts have already spotted this icy traveler.

Astrophotographer Julian de Winter, a junior lecturer at the University of Mons in Belgium, captured Comet Lemon’s striking emerald glow and elongated tail from Texas in late September.

The faint green hue arises from carbon in the gas cloud enveloping the comet’s nucleus.

In the Northern Hemisphere, Comet Lemon will appear near the Big Dipper before dawn from now until mid-month. According to EarthSky, a site focused on astronomy and skywatching, the best viewing time is in the northeast sky, just beneath the distinctive bowl and handle of the Big Dipper.

In about a week, the comet will rise in the western sky and can be seen in the evening sky. From then until the month’s end, visibility of these celestial objects may be challenging, although they might be seen with the naked eye.

Comet Swan is visible in the evening sky until the end of the month. The prime time to locate it is about 90 minutes post-sunset, directed towards the southwest. This comet may not be bright enough for naked-eye observation, so binoculars or a small telescope will be necessary.

In the coming days, Comet Swan will ascend higher in the horizon post-sunset and could brighten as it nears its closest approach to Earth around October 20th.

Under optimal conditions of clear, dark skies with minimal light pollution, it may even be possible to see both comets on the same night towards the month’s end.

Discovered in January by the Lemmon Mission, Comet Lemmon tracks near-Earth objects using telescopes located in Arizona’s Santa Catalina Mountains.

Comet SWAN was identified more recently by amateur astronomers in early September while examining images from NASA’s Solar and Heliospheric Observatory’s SWAN instrument, which has been studying the Sun since its launch in 1995.

Additionally, this month, another type of comet—one originating from outside our solar system—is passing through. Comet 3I/ATLAS, the third identified interstellar visitor, was recently photographed by a spacecraft orbiting Mars and is set to make its closest approach to the Sun around October 30th.