THE SOUTHWORTH PLANETARIUM 70 Falmouth Street Portland, Maine 04103 (207) 780-4249 usm.maine.edu/planet 43.6667° N 70.2667° W Founded January 1970 2022-2023: LI Sunrise: 7:01 a.m. Sunset: 4:04 p.m. Civil twilight begins: 6:28 a.m. Civil twilight ends: 4:37 p.m. Sun's host constellation: Ophiuchus Moon phase: Full Moon Moonrise: 3:32 p.m. Moonset: 7:40 a.m. (12/8/2022) Julian date: 2459921.21 " " -Marcel Marceau THE DAILY ASTRONOMER Wednesday, December 7, 2022 Tonight's Lunar Occultation of Mars *The most fantastic astronomical event in 2022?* -Arguably *One of the most anticipated events in 2022?* -Indisputably! *What are we discussing?* Ahem.. Wednesday, December 7, 2022 *Tonight's Lunar Occultation of Mars* Tonight, the full moon will occult -move in front of- Mars from our perspective. Also, from the perspective of most North American, European and Middle East observers. See the image below: [image: pSucFcE26RgrRuLoCcwyCk-970-80.jpg] Any observer within the region bounded by this curved cylinder will be able to watch the full moon move directly in front of and then eventually away from the planet Mars. Image credit: Sky and Telescope Observers outside of this region will only see the moon appearing to move close to Mars. While such a Mars-moon appulse will dazzle the senses (especially since the moon is full and Mars is at opposition and therefore at its brightest), these other observers won't have the opportunity to watch Mars "blink"out behind the moon. Observing a lunar occultation of a planet is particularly pleasing because, unlike the pinpoint stars that simply "wink" out when the moon passes in front of them, disc-like planets vanish gradually, over a period of 30 - 45 seconds. Tonight, observers in our region will want to venture out around 10:45 p.m. At this time, the Moon will be within less than half a degree of Mars. For the next few minutes, one will see the moon approach and then gradually move in front of Mars. Refer to the following time-line: - Mars will disappear behind the moon at 10:57 p.m. EST. The occultation will occur in the southeastern sky at an altitude of 70.1 degrees - Mars will reappear at 11:24 p.m, altitude 71.3 degrees We'll see this occultation because of a chance alignment between Earth, the moon and Mars. Although lunar occultations of Mars occur approximately once every 14 years, tonight's event is particularly special because the moon is full (100% illuminated) and Mars, being at opposition, is at its biggest (17.06" in angular diameter) and at its brightest (magnitude -1.9: 1.6 times brighter than Sirius.) [image: 2022-December-7-8-alignment.jpg] Tonight, the planets and moon are aligned so as to allow us to watch the moon move directly in front of Mars. Image Credit: Earthsky.org Provided the weather is clear -a dicey issue, actually- one can behold the coupling of Mars and Artemis. Who on Earth would want to miss that? To subscribe or unsubscribe from the "Daily Astronomer" http://lists.maine.edu/cgi/wa?A0=DAILY-ASTRONOMER