Skywatch Line for Monday and Tuesday February 19th, and 20th, 2024 written by Joe Slomka
This is the Dudley Observatory’s Skywatch Line for Monday and Tuesday February 19th, and 20th, written by Joe Slomka.
The Sun sets at 5:32 PM; night falls at 7:06. Dawn begins at 5:12 AM and ends with Sunrise at 6:46.
Gemini hosts the Moon on both nights in the southeast. Monday’s Moon sets at 4:13 AM and rises at 12:33 PM; it appears 82% illuminated, 65° high and 30 arc-minutes in size. Tuesday’s Moon sets at 5:03 AM, rises at 1:34 PM, 55° high, same size, 89% lit and sets at 5:42 AM on Wednesday.
Mercury and Saturn are too close to the horizon for observation. Neptune is the first visible planet, rising in western Pisces; by 7 PM it glows with 8th magnitude, 2 arc-seconds, 6° high and sets at 7:35 PM.
Jupiter dominates the evening sky and shares southwestern Aries with Uranus. The Gas Giant sparkles with minus 2nd magnitude, 37 arc-seconds 46° high at 7:PM and sets at 11:18 PM. Tuesday sees a lot of action for telescopic observation; Jovian moon Europa is occulted (hidden) between 3:34 AM and 6 AM. The Great Red Spot (a giant storm) becomes visible at 4:46 AM. Io transit begins at 9:07 PM and ends at 11:19 PM. Io’s shadow begins at 10:23 PM and ends at 12:34 AM, Wednesday along with the Great Red Spot at 12:38 AM. Uranus trails Jupiter by 9°, shining with 5th magnitude, 3 arc-seconds, 54° high and sets at 12:14 AM.
Venus is the first visible early riser in southeastern Capricornus, it rises at 5:39 AM, blazing with minus 3rd magnitude, 11 arc-seconds, 89% lit, 3° high at 6 AM and 12° at 7 AM. Mars rises at 5:47 AM, shining with 1st magnitude, 4 arc-seconds, 2° high at 6 AM and 11° by 7 AM. Wednesday, 40 minutes before Sunrise, Mars and Venus will be only 0.8° apart.
Comet 12P/Pons-Brooks remains in Lacerta, slightly brighter than last week, 91% lit, 22° high at 7 PM, sets at 9:53PM, re-rises at 3:41 AM and 17° in the Northeast at 6 AM.
Western calendars begin on January First – thanks to Julius Caesar. The 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 modifications, this is the calendar we now use.
Clear Skies Joe Slomka