C/2025 A6 (Lemmon) is a non-periodic comet discovered by the Mount Lemmon Survey in images obtained on 3 January 2025. It has an inbound orbital period of about 1,350 years and will pass perihelion on 8 November 2025 when it will be 0.53 AU (79 million km) from the Sun. This perihelion passage will reduce the orbital period to about 1,150 years. It makes its closest approach to Earth on 21 October 2025 and may be visible to the naked eye 42 degrees from the Sun after sunset. As of 19 October 2025, the comet is about apparent magnitude 4.6, and is visible in binoculars about midway between Arcturus and the handle of the Big Dipper.
C/2025 A6 (Lemmon)
Photographed with the APO 107 mm refractor and ASI 2600MC color CMOS camera in Stuvsta on October 16th, 2025. Exposure was 2 min (single light) with IDAS HEUIB filter. The comet was partly hidden behind a tree, hence the poor image quality.
Comet C/2025 A6 (Lemmon)
Photographed with the APO 107 mm refractor and ASI 2600MC color CMOS camera in Stuvsta on October 18th, 2025. Exposure was 20 * 2 min with IDAS HEUIB filter. Postprocessing in Pixinsight with Comet Alignment, resulting in elongated stars.
Comet C/2025 A6 (Lemmon)
Photographed with the APO 107 mm refractor and ASI 2600MC color CMOS camera in Stuvsta on October 18th, 2025. Exposure was 20 * 2 min with IDAS HEUIB filter. Postprocessing in Pixinsight with Comet Alignment to create an image of the comet without stars which was then added to the correct star backgroubd without comet.
Comet C/2025 A6 (Lemmon)
Photographed with the APO 107 mm refractor and ASI 2600MC color CMOS camera in Stuvsta on October 18th, 2025. Exposure was 20 * 2 min with IDAS HEUIB filter. Postprocessing in Pixinsight with Comet Alignment to create an image of the comet without stars which was then added to the correct star backgroubd without comet.