2023, December 10: Venus-Jupiter Opposition

2023, December 10: Venus, Earth, and Jupiter are in an imaginary line, signaling the Venus-Jupiter opposition.
Chart Caption – 2023, December 10: Venus, Earth, and Jupiter are in an imaginary line, signaling the Venus-Jupiter opposition.


by Jeffrey L. Hunt

Chicago, Illinois:  Sunrise, 7:07 a.m. CST; Sunset, 4:20 p.m. CST.  Check local sources for sunrise and sunset times. Times are calculated by the US Naval Observatory’s MICA computer program.

Today is the Venus-Jupiter opposition.  The two planets are in opposite directions in the sky so that as Jupiter sets Venus rises in the east-southeast.  After this morning the two planets are not visible again at the same time until November 2024.

Venus steps eastward against the background stars quickly while Jupiter is slowly retrograding.  The planets’ positions in the sky are a result of their revolution around the sun. Venus’ year is two hundred, twenty-five days long, while Jupiter revolves around the sun in nearly twelve years.  Venus passes between Earth and the sun on an orbital path that is closer to the sun and speeds away while our planet does the same with Jupiter.  This morning, the three planets are in an imaginary line with Earth placed between Venus and Jupiter, although Jupiter is four times farther away from Earth than Venus.

This morning Venus and Jupiter are visible for only three minutes beginning at three hours, thirty-two minutes before sunrise.  Unlike most celestial bodies, Venus and Jupiter are bright enough to shine through the haze at the horizon that blurs and dims celestial objects.  A clear view toward the respective horizons is required to observe the planets.

When a planet-to-planet opposition occurs with an outer planet in the morning sky, this event is the last time the two worlds are visible in the sky at the same time.  Venus is in the eastern sky and the other planet is in the west.  When these events occur in the evening sky, the event signals that the two planets begin to appear at the same time, Venus in the west and the second planet in the east.

Summaries of Current Sky Events
Summary for Venus as a Morning Star, 2023-24

Here is today’s planet forecast:

Morning Sky

Chart Caption – 2023, December 10: Venus and the crescent moon are in the southeast before sunrise.

An hour before sunrise, brilliant Venus is less than 25° above the southeast horizon and over 12° above a thin crescent moon, 7% illuminated and over 10° above the horizon.

Venus is stepping eastward toward Zubenelgenubi, leading up to a conjunction with the star in a week. This morning, the gap is 8.9° and the moon is 3.9° to the lower right of the star.  Venus is over 13° to the lower left of Spica, Virgo’s brightest star.  The planet passed the star in a wide conjunction on November 29th.

Look for Earthshine on the moon.  This is reflected sunlight from Earth’s oceans, clouds, and land that softly illuminates the moon’s night portion.

Mars is slowly entering the sky, rising less than thirty minutes before the sun, is hidden in bright morning twilight.

Evening Sky

Chart Caption – 2023, December 10: Mercury is low in the southwest at 30 minutes after sunset.

Mercury is beginning a retreat into brighter evening twilight.  At sunset, the speedy planet is over 10° above the southwest horizon.  Thirty minutes later, it is about 6° above the horizon.  At this level of twilight, a binocular is needed to spot the innermost planet. It is getting dimmer each evening.

Chart Caption – 2023, December 10: An hour after sunset, Saturn is in the southern sky.

By an hour after sunset, two planets are easily visible.  Saturn, dimmer that Venus and Jupiter, is over 35° above the southern horizon.  It is slowly moving eastward in front of dim Aquarius, 7.8° to the upper left of Deneb Algedi, meaning “the kid’s tail,” 9.9° to the upper right of Skat, meaning “the leg,” and 10.3° to the lower right of Lambda Aquarii (λ Aqr on the chart).

The star Fomalhaut, slightly dimmer than Saturn, is nearly 10° to the lower left of the Ringed Wonder.

Chart Caption – 2023, December 10: During the early evening, Jupiter is in the east-southeast.

Bright Jupiter is easy to spot in the east-southeast at this hour.  Its retrograde ends in less than three weeks.  This evening it is 11.4° to the lower right of Hamal, Aries’ brightest star, and 14.0° to the upper right of Menkar, part of Cetus.  Use a binocular to see these stars and those with Saturn, especially in urban and suburban settings.

With the binocular look at the Pleiades star cluster, resembling a tiny dipper, and the Hyades cluster, along with the star Aldebaran make a sideways letter “V” that makes Taurus’ head.

During the night the planets and the stars appear farther westward from Earth’s rotation. Saturn sets in the west-southwest less than six hours after sundown.  Jupiter is south about an hour before Saturn sets.  It sets over three hours, thirty minutes before sunrise.


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