December 19, 2022: Before sunrise, the crescent moon approaches the Scorpion’s pincers. After sunset, attempt to spot the bright five planets after sunset.
by Jeffrey L. Hunt
Chicago, Illinois: Sunrise, 7:14 am CST; Sunset, 4:22 pm CST. Check local sources for sunrise and sunset times for your location.
Daylight has reached the shortest time interval for the year, nine hours, eight minutes. Latest sunrise time (7:18 am CST) begins on the 28thth and lasts through January 10th.
Jupiter’s Great Red Spot’s transit times, when it is in the center of the planet in the southern hemisphere: 4:28 UT, 14:24 UT; Dec. 20, 0:20 UT. Convert the time to your time zone. In the US, subtract five hours for EST, six hours for CST, and so on. Use a telescope to see the spot. Times are from Sky & Telescope magazine.
This is the 50th anniversary of the last Apollo lunar mission – Apollo 17. On December 19, 1972, the crew returned to Earth. The command module with Eugene Cernan, Ronald Evans, and Harrison Schmitt landed in the Pacific Ocean.
NASA’s summary of the mission stated, “The Apollo 17 mission was the most productive and trouble-free piloted mission, and represented the culmination of continuous advancements in hardware, procedures, training, planning, operations, and scientific experiments.”
This ended a phase of human exploration of space that placed 12 humans on the moon for brief visits.
Here is today’s planetary forecast:
There is no bright planet in the sky this morning. One hour before sunrise, the crescent moon, 19% illuminated, is about one-third (30°) of the way up in the south-southeast, 11.6° to the lower left of Spica.
The moon is showing earthshine on its night portion. Reflected sunlight from Earth’s oceans, clouds, and land gently illuminates the lunar night.
Note the Scorpion’s pincers, Zubeneschamali and Zubenelgenubi, about 10° to the lower left of the lunar crescent. They are about the brightness of the stars of the Big Dipper.
At this hour the Scorpion seems to be climbing across the southeastern horizon. Today the pincer stars belong to Libra. The Scorpion’s forehead, Dschubba, is nearly 10° above the horizon. Antares, the heart, makes its first morning appearance, known as the heliacal rising, in a few mornings.
Begin looking for the five-planet display. Venus and Mercury are low in the southwest during brighter twilight. At that time the challenge is Saturn. Not as bright as Jupiter or Mars, this outer planet becomes visible about 45 minutes after sunset.
Find a clear horizon, looking towards the southwest. On the 24thththe evening crescent moon joins the view with the two inner planets.
This evening at 30 minutes after sunset, brilliant Venus is about 5° above the southwest horizon to the right of the southwest point. While the planet near the horizon, it is bright enough to be seen without a binocular’s optical assist, in this level of twilight, but one might be needed to initially find it.
One technique that I use is to move – walk either towards or away from the planet’s suspected location to see it compared to a tree or nearby building. If you find it, you can show it to a sky watching companion by referencing the planet to the terrestrial feature. The accompanying photo above, shows the planet referenced to a tree.
Mercury is 5.7° to the upper left of Venus. Both easily fit into the same binocular field of view. The planet is fairly bright. Can you see it without binoculars?
Saturn is over 30° to the upper left of Mercury and the same distance above the south-southwest horizon. It is not bright and likely not visible without optical assistance at this level of twilight.
Point the binoculars in the general direction to slowly sweep the sky either up and down or left to right, in a pattern with overlapping binocular field of views – a grid search.
During the next several minutes, the sky darkens further and Venus and Mercury are lower in the sky. Saturn might be visible during this interval, depending on the clarity of the sky. If so, then look for Mercury and Venus in the southwest, Jupiter in the south-southeast, and Mars in the east-northeast.
Fifteen minutes later, 45 minutes after sunset, Mercury is lower in the southwest and Venus is very low, almost setting, but theoretically visible because of its brilliance.
Saturn is easily in view in the south-southwest and bright Jupiter is in the south-southeast – about halfway up (45°) in the sky.
Mars is in the east-northeast, over 20° above the horizon. The Red Planet is 8.3° to the upper left of Aldebaran and over 20° to the lower right of Capella. Mars is considerably brighter than the two stars.
During the next two hours is the best time to spot the three outer planets, before Saturn is too low in the southwestern sky.
At 6:20 pm CST, Jupiter’s Great Red Spot is in prime viewing for sky watchers with telescopes, at the center of the planet in the southern hemisphere. From Chicago, the planet is over halfway up in the south and in a good viewing location across the Americas. By tomorrow morning, all the planets are below the horizon. The crescent moon is below Zubenelgenubi. Tomorrow evening provides an improving opportunity to see the five planets simultaneously.