C/2025 A6 Lemmon

Closest to Earth:  2025 Oct 20 at 0.59AU
Closest to Sun:   2025 Nov 08 at 0.53AU
Maximum magnitude: 3 in late October 2025
Orbital Period: 1,342 years



 

First observed by the Lemmon survey on January 3, 2025, this long-period comet will pass within 0.53 AU of the Sun on November 8, 2025.
It should reach magnitude 3 and be visible to the naked eye in late October as it nears Earth at 0.59 AU on October 20,
with viewing best from the northern hemisphere.

November 2025 Chart for observers at 35S latitude.

During November 2025,
Southerners should get their first opportunity to view the comet as it enters evening skies during the first week of November,
although viewing conditions will be challenging. You will need a clear horizon to the west after sunset. The further north you are situated, the better.
On November 1, the magnitude 3 comet will situate in twilight, a couple of degrees above the horizon, about 1 hr after sunset at azimuth 262 degrees,
in the constellation of Ophiuchus.
Look for it at about 1 hour after local sunset.
Conditions will slowly improve as the nights progress, with the comet increasing about 1 degree of altitude per night.
Moonlight will interfere with viewing until the evening of the November 7, when the comet should now be spotted in darker skies.
On the night of November 13-14, it will locate adjacent to Eta Ophiuchii (Sabik), a magnitude 2.5 star. The slightly fainter comet is now likely to appear at magnitude 4.0.
Never really escaping evening twilight, the comet will start to become more difficult to observe during the month as twilight encroaches
and by November 23, the now magnitude 5 comet will now probably be too difficult to spot, as it lies 18 degrees east of the Sun.

During December 2025,
the comet is projected to become visible again in the morning sky towards the end of the month, following its solar conjunction earlier in December.
On Christmas morning December 25, the comet makes an appearance very low in the southeastern morning sky in Scorpius, shining at approximately magnitude 9.0.
Conditions slowly improve each night as it treks southwards through Scorpius and by months end can be found about 1.5 degrees east of star cluster NGC 6281.

During January 2026,
the comet will fade from magnitude 9.5 to 11.0 as it treks southwards through the constellations of Scorpius and Ara, best viewable in the hour before dawn.
On January 1, the comet situates about 1.5 degrees east of star cluster NGC 6281.
Moonlight interferes between January 3 to 16.
On January 13, the comet is 20’ west of the third magnitude star Eta Scorpii.
By months end, the now magnitude 11 comet can be found in Ara, some 3 degrees to the north of Eps 1 Ara.

During February 2026,
the comet will gradually fade from magnitude 11.0 to 12.0 as it moves southward through the constellations Ara and Norma.
The best time to observe it will be just before dawn; however, because of its southerly declination,
many viewers in the southern hemisphere will find it circumpolar and thus visible throughout the night.
On February 11, the comet will be situated inside the star cluster NGC 6208 in Ara.
On February 23, it will be 45’ southeast of star cluster NGC 6087 in Norma.
By months end, the now magnitude 12 comet lies 30’ to the east of star cluster NGC 6025 in Triangulum Australae.

During March 2026,
the comet will gradually fade from magnitude 12.0 to 12.5 as it moves southward through the constellations Triangulum Australis, Circinus and Musca
deep in southern circumpolar skies, however, thee best time to observe it will be just before dawn.
On March 1, the magnitude 12 comet lies just south of star cluster NGC 6025 in Triangulum Australae.
On March 13, it lies 30’ north of magnitude 12 planetary nebula NGC 5844.
On March 17, I lies adjacent to Alpha Circinii.
On March 27, it lies a degree north of the S shaped planetary nebula NGC 5189.
By months end its time to say goodbye to comet Lemmon, not to return for another 1,335 years.