December 17, 2022: The thick morning crescent is near Porrima in Virgo this morning. A nighttime display of the five bright planets begins to form.
by Jeffrey L. Hunt
Chicago, IL: Sunrise, 7:13 a.m. CST; Sunset, 4:21 p.m. CST. Check local sources for sunrise and sunset times for your location.
Transit time of Jupiter’s Great Red Spot, when it is in the center of the planet in the southern hemisphere: 2:50 UT, 12:45 UT, 22:41 UT. Convert the time to your time zone. In the US, subtract five hours for EST, six hours for CST, etc. Use a telescope to see the place. The hours are from Sky & Telescope magazine.
It’s the 50e anniversary of the last Apollo lunar mission – Apollo 17. On December 17, 1972, on his way back to Earth, Ronald Evans left the command module for a 65-minute excursion to retrieve film cartridges and data films of the experiment bay in the service module.
Here is today’s planetary forecast:
An hour before sunrise, the thick crescent moon, 39% illuminated, is about halfway up south-southeast and 1.5° to the right of Porrima, also known as Gamma Virginias. The moon covers or occults the star for skywatchers in Hawaii, as of 3:30 a.m. HST. This is the last lunar occultation of a bright star of the year.
At the waning crescent phase, the moon begins to show the earth’s glow, sunlight reflecting off Earth’s oceans, clouds, and land. This light gently illuminates the lunar night. A binocular or spotting scope makes the view clearer. A tripod-mounted camera with a short exposure captures the scene.
The morning sky is devoid of bright planets, although Mars is barely above the western horizon at this time. The view of the solar system turns to the evening sky, where a five-planet display begins to form shortly after sunset.
Mars and Venus are always a challenge. Thirty minutes after sunset, Venus is less than 5° southwest, about 8° to the right of the southwest point. At this time, the planet is likely visible without the optical assistance of binoculars, but assistance may be needed to initially locate the planet.
Mercury is 5.9° upper left of Venus. Both fit into a binocular field of view. Can you see Mercury without binoculars.
Mercury reaches its greatest angular separation from the sun on the 21stst. From 24e, the crescent moon enters the scene. Both planets and the crescent moon are low in the western sky 45 minutes after sunset. If you haven’t spotted Venus, start looking for a place with a clear horizon to the southwest, so you can search for all five planets simultaneously for about four evenings. After that, Mercury is still present, but its brightness begins to fade rapidly.
Skywatchers at more southern latitudes have a better view of both planets, higher in the sky and worlds can be found a little later in slightly darker skies
At this time interval after sunset, Saturn is not visible at about 35° upper left of Mercury.
The Ringed Wonder is easily visible an hour after sunset. It is about a third of the height in the south-southwest. It moves east against the stars of eastern Capricorn. Tonight, Saturn is 1.6° from Nashira. The planet passes 1.3° from the star on the evenings of the 27e and 28e. Follow the path of the planet every clear evening with a binocular.
Bright Jupiter is nearly 40° upper left of Saturn. It is the brightest star in the sky tonight, especially after Venus sets. Being further east and away from the glare of early evening western twilight, Jupiter is likely visible when looking for Venus and Mercury.
Jupiter is moving east against a dark star field in Pisces, much darker than those in Saturn’s celestial position tonight.
Mars, also likely visible low to the east-northeast when Mercury and Venus are visible, is a little higher in the sky an hour after sunset. The planet is 8.4° upper left of Aldebaran, the brightest star in Taurus.
The Red Planet continues to retrograde ahead of Taurus. He returns to Aldebaran on the 26the and completes his demotion on January 12. Mars passes Aldebaran for the third and final conjunction on January 30e.
For the next 90 minutes or so, the three bright outer planets are easy to see simultaneously as they move further west. Look for them before Saturn disappears behind obstacles to the southwest.
Tomorrow morning, Mars could be visible very close to the horizon to the west-northwest. For practical observations, it disappeared into the thicker layers of the atmosphere near the horizon.
Meanwhile, the crescent moon is near the star Spica about an hour before daybreak.
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