Skywatch Line for Monday, and Tuesday, December 30th and 31st, 2019

This is the Skywatch Line for Monday, and Tuesday, December 30th and 31st, written by Joe Slomka.

The Sun sets at 4:29 PM; night falls at 6:12. Dawn begins at 5:44 AM and ends with the Sun rising at 7:25.

Early evening holds a dramatic trio in the southeast. Monday’s Moon, next to Aquarius, blazes with minus 9th magnitude, appears nearly 30 arc-minutes in size, is 20% illuminated and sets at 9 PM. Venus, to the Moon’s left, occupies Capricornus, blazes with minus 9th magnitude, appears 13 arc-seconds in size and sets at 9:10 PM. Tuesday evening, the Moon moved within Aquarius, appears nearly the same size, but is brighter and sets at 10 PM; Venus apparently is stationary. Saturn, in Sagittarius, to Venus’ lower left, shines with zero magnitude and appears about 15 arc-seconds in size; the Ringed Planet is very low in the southwestern sky and is soon lost in twilight’s glare. It sets at 5:23.

Nightfall reveals Neptune, Uranus and 4Vesta. Neptune, in Aquarius, is moderately high in the southwestern sky. It shines with 8th magnitude, is 2 arc-seconds in size and sets at 10:04 PM. Uranus occupies Aries, is brighter, slightly larger and higher in the southern sky; it sets at 2:08 AM. Asteroid 4Vesta lingers in Cetus’ tail. It shines with 7th magnitude, is best observed at 8:06 PM and sets at 2:44 AM. Finder charts for all three can be obtained from astronomy magazines and websites.

Mars rises in Libra at 4:15 AM and is the only planet visible. The Red Planet glows with 1st magnitude, appears about 4 arc-seconds in size and is 14° altitude by 6 AM.

Wednesday is, of course, New Year’s Day. Other cultures celebrate different days. For some, it is the Spring Equinox, others the Winter Solstice. Ancient Egyptians marked the rising of the star Sirius. Chinese celebrate New Year’s between January 20th and February 20th due to a lunar calendar. New Year’s Day also varies in the lunar Islamic calendar. Western calendars begin on January First – thanks to Julius Caesar. The early Roman calendar was a mess; it contained 354 days. Extra months had to be inserted to keep in step with the Sun. While Caesar courted Cleopatra, he met her astronomer, Sosigenes, who recommended calendar reform. Caesar adopted those suggestions. On January First 45 BC, the new calendar became effective. It called for 365 days and twelve months. A leap year would be added every four years, to keep the calendar in sync with the Sun. With minor changes, this is the calendar we now use.

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