Skywatch Line for Friday, January 23, through Sunday, January 25, written by Sam Salem
This is Dudley Observatory’s Skywatch Line for Friday, January 23, through Sunday, January 25, written by Sam Salem.
On Friday, Sun rises at 7:18am and sets at 4:57pm; Moon rises at 9:36am and sets at 10:26pm.
On Friday, the Moon passes 4° north of Saturn at 8am, then passes 4° north of Neptune at 11am. The trio stands in the southwestern sky on Friday evening and remains visible for several hours after sunset. Watch the two planets around 6:30pm. as they are roughly 40° high, far enough above the horizon that you have a good chance to catch Neptune before it sinks into the turbulent air near the ground.
Saturn, magnitude +1.1 at the Aquarius-Pisces border, is easy to spot below the crescent Moon. It’s brighter than any star in this part of the sky. In a telescope, look at Saturn and its ring system, stretching 37” from end to end and tilted just under 2° to our line of sight. Look for Titan, the planet’s largest and brightest moon, shining around magnitude 8.5 some 1.7’ east of Saturn’s center. Saturn sits lower left of the Great Square of Pegasus. It descends through the evening and sets in the west around 9pm.
Neptune is only visible in binoculars or a telescope. It lies 2.2° northeast of Saturn, roughly ⅓ of the distance along a line drawn from Saturn toward the Moon. Neptune spans only 2” on the sky and shines at magnitude 7.8. It will appear as a “flat” bluish-gray star in the eyepiece.
First Quarter Moon occurs at 11:47pm. on Sunday. The Moon shines in the constellation Aries. Spot Alpha Arietis and dimmer Beta Arietis a few degrees to the Moon’s upper right. First quarter Moon rises around noon and sets around midnight.
On the half-lit Moon, the sunrise terminator is just beginning to unveil Mare Imbrium in the lunar north. The Alps and Apennine mountain ranges outline Imbrium’s early sunlit rim standing out in long-shadowed relief. The terminator from the center of the lunar disk southward crosses the heavily cratered Southern Highlands. Barely beyond the dark edge of the terminator, find some tiny, starlike speck of a peak catching the very first rays of the Sun.
Jupiter, magnitude –2.6, shines in the Pollux stick figure of the Gemini twins. It shines low in the east-northeast during dusk, dominates the east after dark, then later the high southeast. Jupiter is 1° or so of Delta Geminorum, magnitude 3.5. Watch them pull a little farther apart each night. Jupiter is highest in the south by 11 pm. It’s a big 47 or 46 arcseconds wide all week.
Sunday marks the 22nd. anniversary of NASA’s Opportunity rover landing on Mars. On January 25, 2004, Opportunity Rover landed at Meridiani Planum, exploring for signs of past water, discovering hematite “blueberries,” and vastly exceeding its 90-day design life before its mission ended in 2019 after a massive dust storm, making it the longest-running Mars rover ever. It was one of twin rovers, with its sister rover, Spirit, landing few days earlier on January 3, 2004.