January 18, 2023: Mercury and the crescent moon appear in the eastern sky before sunrise. After sundown, Venus continues to approach Saturn leading to a conjunction in four nights.
by Jeffrey L. Hunt
Chicago, Illinois: Sunrise, 7:14 a.m. CST; Sunset, 4:48 p.m. CST. Check local sources for sunrise and sunset times for your location. Times are calculated from the U.S. Naval Observatory’s MICA computer program.
Jupiter’s Great Red Spot’s transit times, when it is in the center of the planet in the southern hemisphere: 9:24 UT, 19:20 UT; Jan. 19, 5:16 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.
Here is today’s planet forecast:
Morning Sky
An hour before sunrise, the waning crescent moon, 16% illuminated, is 15° above the south-southeast horizon. It is 1.9° to the left of Antares, the brightest star in Scorpius.
The Scorpion continues its climb into the morning sky.
The moon’s night portion is showing earthshine – reflected sunlight from Earth’s oceans, clouds, and land.
At this hour, Mercury is nearly 4° up in the east-southeast, but wait another fifteen minutes to see it higher against the blush of morning twilight.
Mercury does not have any bright stars nearby to help with its identification and it is beyond a binocular field from the moon’s crescent, over 27° to the lower left of the lunar orb. It is the brightest star near the eastern horizon at this time. During the next few mornings, the speedy planet continues to rise earlier and gain brightness.
Today, Mercury stops retrograding, appearing to move westward compared to the starry background. When the planet moves from the evening sky to a morning view, it passes between Earth and the sun. When it does this, it moves from east of the sun to west and in doing so, it moves westward or retrograde.
The planet reaches its greatest separation from the sun on the 29th, rising 88 minutes before sunrise.
Evening Sky
Forty-five minutes after sundown, brilliant Venus is nearly 10° above the west-southwest horizon, 4.5° to the lower right of Saturn. Their conjunction is in four nights.
Venus moves over 10 times farther eastward than Saturn from night to night as it closes in on the Ringed Wonder. They appear close together in the sky, but Saturn is nearly seven times farther away. Without depth perception in space, all the celestial wonders appear at the same distance.
Bright Jupiter is about halfway up in the sky in the south-southwest, less than 45° to the upper left of Venus. After the conjunction with Saturn, Venus moves toward Jupiter and passes it on March 1st.
Mars is farther eastward, over 50° above the east-southeast horizon and 8.5° to the upper left of Aldebaran, the brightest star in Taurus. The Red Planet is slowly marching eastward and picking up the cadence. It passes the star on the 30th for the third meeting in a triple conjunction series.
Regular readers and podcast listeners note that for several evenings Mars is about 8.5° from Aldebaran. The planet is moving slowly. With the precision used in these articles, Mars seems to be stationary, but it appears to be moving slowly against the sidereal backdrop.
Later during the evening, the stars behind Mars come into view. They make the constellation Taurus. The head is outlined by the Hyades star cluster and Aldebaran. Elnath and Zeta Tauri dot the long horns and the Pleiades star cluster ride on the Bull’s back. Use a binocular to spot the star clusters.
Through the binocular, note that Venus and Saturn are in the same field of view with the pending conjunction. With Venus to the lower right in the field of view, Saturn is to the upper left. The Evening Star is 2.4° to the lower right of Nashira, while Saturn is 1.4° to the upper right of Deneb Algedi. During the next two evenings, watch Venus pass Nashira and close gap to Saturn to 2.2°.
Jupiter’s Great Red Spot is not easily visible during the nighttime hours across North America. NASA recently described a 40-year study of Jupiter’s atmosphere. The study found that Jupiter’s temperatures rise and fall following definite periods that are not tied to the seasons or any other cycles scientists know about. The photos above from the European Southern Observatory show that the Red Spot is smaller than it was years ago.
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