2023, January 26: Mercury’s Morning Appearance, Bright Evening Planet Parade


January 26, 2023: Mercury is the lone bright planet in eastern morning sky before sunup.  Four bright planets – Venus, Jupiter, Mars, and Saturn – and the moon parade in the evening sky.

Photo Caption – 2016, January 28: Venus and Mercury before sunrise in the eastern sky.


by Jeffrey L. Hunt

Chicago, Illinois:  Sunrise, 7:09 a.m. CST; Sunset, 4:58 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: 6:05 UT, 16:01 UT; Jan. 27, 1:57 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

Chart Caption – 2023, January 26: Mercury is visible low in the southeastern sky before sunrise.

Rising over 90 minutes before sunup, Mercury is nearly 7° above the southeastern horizon 45 minutes later.  The speedy planet is nearing its greatest angular separation from the sun.

The planet is to the lower right of the star Altair, nearly 20° up in the east, and lower left of Antares, about the same altitude as Altair in the south-southeast.

We do not often see the planet when the sky is completely dark.  It revolves around the sun every 88 days at a solar distance that is less than 40% earth’s orbital distance.  The planet does not venture far from the sun from our vantagepoint.

After the planet passes between Earth and the sun, known as inferior conjunction, it pops into the morning sky – racing away into the distance.  It seems to swing around the outer extent of its orbit – greatest elongation – and then plunges back into the sun’s glare.

The chart associated with today’s view of Mercury’s shows the planet’s imaginary orbital path that is above the horizon during mid-twilight, the direction the planet is moving, and this morning’s location.

Find a clear horizon looking to the southeast.  A binocular helps with the initial identification of the planet.

Evening Sky

Chart Caption – 2023, January 26: Venus, Saturn, Jupiter and the moon are in the southwestern sky after sundown.

Step outside after sunset.  The waxing crescent moon, 33% illuminated, is over halfway up in the southwestern sky and over 10° to the upper left of bright Jupiter.  The moon and Jupiter are part of the evening planet parade of four bright planets and two dimmer ones.

At forty-five minutes after sunset, brilliant Venus is to the lower right of the Jupiter-Moon combination.  It is over 10° above the west-southwest horizon and 4.7° to the upper left of Saturn.  The gap between the two worlds grows over 1° each evening.

Saturn is slipping into brighter twilight, and by month’s end, it is difficult to locate without a binocular.  On February 16th, Saturn passes behind the sun at solar conjunction, then slowly climbs into the morning sky.

Jupiter is the next bright planetary target for Venus. Their conjunction occurs on March 1st.  Before then Venus passes 0.6° from dimmer Neptune on February 15th.

The Venus-Jupiter gap this evening is over 35°.

Chart Caption – 2023, January 26: Mars is high in the east-southeast during the evening. Taurus forms the sidereal backdrop.

At this hour, Mars is high in the east-southeast approaching the wide and third conjunction with Aldebaran on the 30th.  This evening, the planet is 8.2° to the upper left of the star.

As Earth pulls away from Mars, the Red Planet dims in brightness, but it is brighter than all the stars in Taurus, its celestial backdrop when the sky darkens further.

Uranus is in front of Aries to the west of the Pleiades star cluster.  The starfield behind the planet is relatively non-descript. In two evenings, Uranus and the moon fit into the same binocular field of view.

Photo Caption – This Hubble Space Telescope view of Jupiter, taken on June 27, 2019, reveals the giant planet’s trademark Great Red Spot, and a more intense color palette in the clouds swirling in Jupiter’s turbulent atmosphere than seen in previous years. The colors, and their changes, provide important clues to ongoing processes in Jupiter’s atmosphere.

At 7:57 p.m. CST, Jupiter is over 20° above the west-southwest horizon.  This is an unfavorable place to look for Jupiter’s Red Spot, but the “storm” is in the center of the planet in the southern hemisphere through a telescope.

At this altitude – height above the horizon, the telescope is looking through a thicker layer of Earth’s atmosphere, blurring the image and sometimes making the planet shimmer like looking across a hot pavement during summer.

Sky watchers farther westward see the planet higher in a clearer sky.

The window to see the long-lived atmospheric disturbance is closing for this appearance of Jupiter. The planet is lower each evening after sunset until it disappears into evening twilight in about two months.



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