The Next Full Moon is a Partial Lunar Eclipse; a Supermoon; the Corn Moon; and the Harvest Moon – NASA Science

Saturday morning, October 12, at 11:10 AM, Comet C/2023 A3 (Tsuchinshan-ATLAS) will be at its closest to Earth. If it survives its pass by the Sun this will likely be when it will be near its brightest. Although it will be on the horizon as evening twilight ends on Friday, our first chance to see it above the horizon as it emerges from the glow of dusk likely will be Saturday evening, when the comet will be 4 degrees above the western horizon as evening twilight ends (at 7:31 PM EDT), similar in altitude and to the right of Venus. Over the next few nights the comet will likely dim as it moves away from the Earth, but also appear higher in the sky and set later each evening, giving us more time and darker skies to look for this comet. As evening twilight ends on October 13 it will be 10 degrees above the western horizon, 12 degrees on October 14, 16 degrees on October 15, etc. Current brightness curves predict it will dim quickly and will be below magnitude 6 by the end of October. How bright the comet will be and how quickly it actually dims will depend upon the gas and dust it is giving off, which can vary quickly and unpredictably, but it could be a good show in the evenings after October 12.