On the night of October 1st, 2025, I captured this image of Comet C/2025 A6 (Lemmon) as it glided across the starry sky. This comet, discovered earlier in 2025 by the Mount Lemmon Survey in Arizona, has been steadily brightening and is now becoming a fascinating target for both amateur and professional astronomers.
In the image, you can clearly see the comet’s greenish coma, a result of diatomic carbon (C₂) fluorescing in sunlight, and its developing tail extending away from the Sun. These features make “Lemmon” a striking reminder of the icy wanderers that visit the inner Solar System from the distant Oort Cloud.
Observing comets like Lemmon requires a dark sky, and October nights provide excellent opportunities to follow its evolution. Over the coming weeks, the comet will continue to shift position against the background stars, gradually changing in brightness and appearance.
Image taken on October 1st, 2025 – Prades (Catalonia, Spain).
The full image covers an area of 2º56′ x 2º16′ at a resolution of 2.13″/pixel.
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Image Details
13028HNT:
16×120″ (32′)
Calibrated with darks, flats, dark-flats.
Total exposure: 32′
Average Moon phase at 61% (not visible during captures)
Image resolution: 2.13”/pixel
FOV: 2º56 x 2º16′
Equipment
13028HNT+ ASI2600MC + Lquad filter
ZWO EFW 7 pos + ZWO EAF
AM5 mount
ASI AIR PLUS
Guiding with ASI120MM and ZWO Mini Guide Scope
Software
ASI AIR, APP, PIX, TPZ, PS.
Aleix Roig, October 2025.
Prades (Tarragona, Catalonia – Spain).