Comet Lemmon 2025A6: October-November 2025
This comet was discovered by the Mount Lemmon Survey on January 3, 2025. It was reached perihelion on 8 November 2025 at a distance of 0.53 AU. Inital brightness estimates indicted the comet was not going to be very bright but, as the comet approached the inner solar system, its observed magnitude was above the predicted curve. Revised estimates put the comet as bright as first magnitude but more conservative values had it between 3rd and 4th magnitude. I first saw the comet on 1 October when it was a morning sky object around 5th to 6th magnitude. By October 12th, it had moved to the evening sky and slowly increased in elevation over the western horizon. By October 21st, the comet reached a magnitude of about +3-+4 and was sporting a tail of about 10 degrees. After this, the moon began to interfere. By November 8th, when I last saw the comet, it was low in the SW at a magnitude of about +5-+6. For the most part this was not a visual comet even though I could see it with the naked eye on several occasions. The ion tail showed multiple changes throughout the apparition.
The comet in the early morning sky. A stack of 42 (10/4) /40 (10/5) ninety-second exposures using a ASI 2600MC camera and 8-inch F5 reflector with Sky Watcher comaa corrector.
These images were taken with an ASI 2600 MC and 8-inch F5 reflector with Sky Watcher coma corrector.