本月下旬，两颗彗星有望同现夜空，或将肉眼可见

Core Points - The C/2025A6 (Lemmon) comet is becoming increasingly bright and is expected to reach a visible brightness around October 21 and November 8, making it observable to the naked eye under good conditions [1][2] - The comet was discovered by astronomers at the Lemmon Mountain Observatory in January 2025 and has shown significant brightness increase since mid-August [1] - The brightness of the comet is forecasted to reach around magnitude 2 at its peak, with a more conservative estimate of magnitude 4, which can be viewed with binoculars [1] Observation Details - The Lemmon comet will appear in the northeastern sky before dawn in early October, transitioning to the western sky in the evenings by late October to early November, which is its brightest phase for northern hemisphere observers [2] - Another comet, C/2025 R2 (SWAN), discovered on September 12, is also visible, with its brightness improving in early October, making it observable in the southwestern sky after dark [2] - The peak of the Orionid meteor shower will coincide with the visibility of both comets on the night of October 21-22, with approximately 20 meteors observable per hour [2]