2023, December 3: Sliced Moon, Three Bright Planets

Moon and Venus, October 13, 2020
Photo Caption – 2020, October 13: The moon (26.0 days past New moon phase, 16% illuminated) – nearly 33° up in the east – is 8.8° above Venus, 24.0° up in the east. The crescent is 5.9° to the lower left of Regulus.


by Jeffrey L. Hunt

Chicago, Illinois:  Sunrise, 7:01 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.

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 3: Before sunrise, the gibbous moon is near the Sickle of Leo.

A week before their planet-to-planet opposition, Venus is low in the east-southeast and Jupiter is low in the western sky.  They are bright enough to shine through the haze at the horizon that blurs and dims celestial objects.  This morning they are over 170° apart.  Find them before Jupiter sets about three hours before sunrise.

At one hour before daybreak, the slightly gibbous moon, 66% illuminated, is high in the southwest, near the Sickle of Leo and Regulus, the constellation’s brightest star.  The lunar orb is 8.8° to the right of the Lion’s brightest star.

The sickle resembles a backwards question mark, but is namesake is the farmer’s harvesting tool with a curved blade and a handle, giving the appearance that the implement is ready to slice the moon.  Eta Leonis (η Leo on the chart), dimmer than the Big Dipper’s stars, is 6.2° to the upper left of the moon.  Use a binocular to spot it.  Later today from Madagascar and southern Africa, the moon occults or eclipses this star.  This occurs before moonrise in the Americas.

The moon is at the Last Quarter phase at 11:49 p.m. CST tomorrow.

Chart Caption – 2023, December 3: Venus and Spica are in the southeast before sunrise.

Farther eastward, Venus is over 25° up in the southeast and 6.1° to the lower left of Spica.  A few mornings ago, Venus passed the star in a wide conjunction.  It is heading toward Zubenelgenubi, the Scorpion’s northern claw, 17.0° to the planet’s lower left and over 10° above the horizon.  This star is about the brightness of the dipper’s stars.

Venus is lower in the sky each morning.  This morning it rises nineteen minutes short of four hours before sunrise.  By month’s end, it loses over forty minutes of rising time compared to daybreak.  It appears noticeably lower in the sky from week to week.

Mars is west of the sun, meaning that it rises before sunrise, but it is not high enough in the sky for easy observation.  The Red Planet rises twenty minutes before the sun, becoming visible later next year.

Evening Sky

Chart Caption – 2023, December 3: Mercury is in the southwestern sky, 30 minutes after nightfall.

Mercury is at its greatest elongation tomorrow.  At sunset, the planet is nearly 10° up in the southwest.  This is not a good appearance for the solar system’s innermost planet for northern hemisphere sky watchers.  By thirty minutes after sundown, it is about 6° above the horizon.  In the bright twilight, use a binocular to see the planet.

Chart Caption – 2023, December 3: Saturn is in the south, in front of Aquarius, during the evening.

Saturn is farther south during the early evening. One hour after sunset, the Ringed Wonder is over 35° above the horizon.  It is slowly trekking eastward in front of Aquarius, 10.7° to the lower right of Lambda Aquarii (λ Aqr on the chart), 10.2° to the upper right of Skat, the Aquarian’s leg, and 7.5° to the upper left of Deneb Algedi, meaning “the kid’s tail.”

Look for the star Fomalhaut, the mouth of the Southern Fish, nearly 20° to the lower left of Saturn and slightly dimmer than the planet.

Chart Caption – 2023, December 3: An hour after sundown, bright Jupiter is in the eastern sky.

Bright Jupiter is easy to spot at this hour, over 30° up in the east.  This planet retrogrades in front of Aries, 11.3° to the lower right of Hamal, the Ram’s brightest star, and 13.7° above Menkar, Cetus’ nostril.  The planet is noticeably west of an imaginary line from Hamal to Menkar.

Chart Caption – Jupiter’s retrograde motion against the starfield is demonstrated for 2023.

The illusion of retrograde continues until month’s end.  It then begins to move easttward compared to the starfield.

Chart Caption – 2023, December 3: As midnight approaches, the moon and the Sickle of Leo are in the eastern sky.

As the midnight hour approaches, the gibbous moon, 59% illuminated, is low in the east-northeast, 3.6° to the left of Regulus and 3.5° below Eta Leonis.  This morning the moon was west of this star.

Saturn sets in the southwest over an hour before moonrise.  Jupiter is south about five hours after sunset, setting in the west nearly three hours before sunrise, when Venus is low in the east-southeast.


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