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: LV Sunrise: 7:07 a.m. Sunset: 4:04 p.m. Civil twilight begins: 6:34 a.m. Civil twilight ends: 4:37 p.m. Sun's host constellation: Ophiuchus Moon phase: Waning Gibbous (67% illuminated) Moonrise: 10:08 p.m. Moonset: 11:56 a.m. (12/15/2022) Julian date: 2459928.21 "This world is but a canvas to our imagination." -Henry David Thoreau THE DAILY ASTRONOMER Wednesday, December 14, 2022 December 2022 Night Sky Calendar Part II *FRIDAY, DECEMBER 23: NEW [SUPER] MOON* Wait?! Isn't a supermoon a full moon that occurs when the moon is at or near perigee, its point of least distance from Earth? Yes, that is one definition of a supermoon. A supermoon is also defined as a new moon that is at or near perigee. Although we can't see anything, a new super moon causes higher than usual tides. In fact, not only is the moon new around the time of perigee, but Earth is very close to perihelion (Jan 4, 2023). Since the Sun's influence on the tides is 44% that of the moon's, having the perigean moon close to perihelion day will cause particularly high POSEIDON tides. *SATURDAY, DECEMBER 24: MOON AT PERIGEE* The moon reaches perigee, its point of least distance from Earth. At the moment of perigee, the moon will be 358,270 kilometers (222,127 miles) from Earth. The occurrence of perigee around the time of the new moon will produce higher than usual tides. (See the previous entry). *MONDAY, DECEMBER 26: MOON NEAR SATURN* See the waxing crescent moon (15% illuminated) as it passes south of Saturn. One will find both bodies within the constellation Capricornus. They will both set by 8:08 p.m. As Saturn is the dimmest of the naked eye planets (magnitude 0.8), it will be helpful to have the moon "close by" to guide you to it. *THURSDAY, DECEMBER 29: MERCURY 1.4 DEGREES N OF VENUS* Ordinarily, a planet-planet appulse proves to be quite a spectacular sight. However, this close coupling of Hermes and Aphrodite will be difficult to see by virtue of their low positions along the western evening horizon. Mercury will set at 5:25 p.m. Venus sets at 5:21 p.m. At magnitude -3.8, Venus will be 58 times brighter than Mercury. *THURSDAY, DECEMBER 29: MOON NEAR JUPITER (BRONZE EVENT!)* Tonight we'll watch the king planet passing north of the first quarter moon. As Jupiter (magnitude -2.3) remains brighter than Sirius, this moon-Jupiter appulse will appear particularly lovely. See them both descending in the western evening sky before setting by 11:10 p.m. *PLANET WATCH* [NOTE: Beginning around the second week of December, all five naked eye planets will be visible in the evening sky.] *MERCURY:* Always elusive owing to its close proximity to the Sun and its rapid revolutionary speed, Mercury lurks low in the western evening sky this month. Although it never veers far from the Sun. Mercury can be viewed soon after sunset. VERDICT: If you can dash outside soon after sundown and find an unobstructed western horizon, you might catch a glimpse of the first world. *VENUS: * After a brief hiatus, Venus returns to the western evening sky. Although it is at its minimum brightness (magnitude -3.8), Venus remains 2.5 times brighter than Sirius. The only issue is its position. Venus lingers low along the western horizon this month and so, despites its brightness, won't be particularly easy to spot. VERDICT: Venus will become a brilliant evening sky beacon early next year, so don't worry if you can't find it this month. *MARS:* [PICK PLANET!] This is the best time to see Mars! On December 8th, it was at opposition, meaning that Earth passed between it and the Sun. At that time, Mars was visible all night and at its brightest. Though dimmer than Jupiter, Mars will remain brighter than Sirius throughout December. VERDICT: All you have to do is venture out early to see the red planet passing north of Orion. *JUPITER: *Look for Jupiter high in the western sky at the beginning of the night. One can find the monster planet loitering south of the Great Square of Pegasus the Winged Horse. Although it doesn't dazzle as it did in September, at magnitude -2.3, Jupiter remains twice as bright as Sirius. VERDICT: Easy peasy! Look for the brightest "star-like" object in the western sky. *SATURN: *The most distant of the naked eye planets is also the dimmest. However, at magnitude 0.8 still appears as bright as Aldebaran, the brightest star in Taurus the Bull. At the beginning of the month, Saturn sets just after 9 o'clock. At month's end it will vanish by 7:45 p.m. VERDICT: The earlier in the month the better for Saturn seekers. However, one should be able to see it anytime this month. The sixth world will vanish into the dusk next month! To subscribe or unsubscribe from the "Daily Astronomer" http://lists.maine.edu/cgi/wa?A0=DAILY-ASTRONOMER