October 17, 2023: The crescent moon is with Scorpius during evening twilight. Venus and Jupiter gleam from the predawn sky.
by Jeffrey L. Hunt
Chicago, Illinois: Sunrise, 7:05 a.m. CDT; Sunset, 6:06 p.m. CDT. Check local sources for sunrise and sunset times. Times are calculated by the US Naval Observatory’s MICA computer program.
No day at Chicago’s latitude experiences precisely eleven hours of daylight this year. Today and tomorrow the length is within a minute of that mark. After today, daylight is less than eleven hours until February 24, 2024.
Today the star Spica is in conjunction with the sun. This means that the sun is between Earth and the distant star, with the sun’s brilliance overwhelming our view. Spica returns to the morning sky early next month.
Antares, now in the southwestern evening sky, is the next bright star to pass solar conjunction on December 2nd. Look for the crescent moon near the star during the next few evenings.
Summaries of Current Sky Events
Summary for Venus as a Morning Star, 2023-24
See this week’s highlights article.
Here is today’s planet forecast:
Morning Sky
Jupiter’s Great Red Spot is visible twice through a telescope during this calendar day from the middle states. The first appearance occurs at 12:23 a.m. CDT. The second occurs two Jupiter days later at 8:14 p.m. CDT.
Venus, less than a week, before its greatest separation from the sun, rises nearly four hours before daybreak. It stands about 30° up in the east-southeast at one hour before sunrise and gleams through brighter twilight as the sun nears the eastern horizon.
The Morning Star is stepping eastward in front of Leo, 7.5° below Regulus, the Lion’s brightest star. Their conjunction occurred October 9th. Yesterday, Venus passed Rho Leonis (ρ Leo on the chart). This morning Venus is 1.3° to the lower right of that star.
In less than a week, Venus passes nearly 10° from Chertan, in the Lion’s haunches, making a wide conjunction. The star’s name means “the two small ribs.”
Jupiter, the second brightest starlike body this morning, is about 30° above the western horizon, nearly matching Venus’ altitude – height above the horizon. The Jovian Giant is 12.3° to the left of Hamal, meaning the “full-grown lamb,” and 11.3° to the upper right of Menkar, meaning “the nostril.” It is about 20° below the Pleiades star cluster that rides on the back of Taurus. The Bull’s head is made by Aldebaran and the Hyades star cluster.
Jupiter is retrograding as opposition nears next month. It passes between Hamal and Menkar on the 28th.
Mercury reaches superior conjunction in three days and it is hiding in sunlight, rising only ten minutes before the sun.
Evening Sky
Mars is also hiding in bright sunlight, setting twenty-six minutes after the sun.
At forty-five minutes after sunset, the crescent moon, 11% illuminated, is only 5° above the southwest horizon. It is at the Scorpion’s head, near Graffias, Dschubba, and Pi Scorpii (π Sco on the chart). Dschubba is known as the Scorpion’s forehead or crown.
With the scene’s low altitude, use a binocular to see the stars, along with earthshine, from sunlight reflecting from Earth’s oceans, clouds, and land that softly illuminates the lunar night.
Look for Antares, 8.2° to the upper left of the lunar crescent. This star disappears into evening twilight near Halloween – known as its heliacal setting. It sets within a minute of sunset, known as the star’s cosmic setting, November 24th, at Chicago’s latitude.
Overnight from Southeast Asia, the moon occults or eclipses Sigma Scorpii (σ Sco on the chart).
As the sky grows darker, find Saturn nearly 30° up in the southeast at an hour after sundown. It is not as bright as Jupiter or Saturn, but outshines most stars this evening. It is retrograding in front of Aquarius, 6.9° to the left of Deneb Algedi, Capricornus’ tail.
Look for Fomalhaut, the mouth of the Southern Fish, about 20° below Saturn. Its presence in the evening sky is a signal that autumn has arrived.
Saturn is in the south about four hours after sundown. It sets over four hours before sunup and before Venus rises.
At this hour Jupiter is low in the east-northeast. It is bright enough to be seen near the horizon, through the haze that filters and blurs celestial objects.
By two hours after sundown, Jupiter is nearly 15° up in the east, below Hamal and to the upper right of the Pleiades. Near midnight it is about halfway up in the east-southeast. Tomorrow morning it is in the western sky again.
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December 19, 2023: Before sunrise, Venus appears below the Scorpion’s claws. After sundown, the moon is nearly midway from Saturn to Jupiter. - 2023, December 18: Pinched Venus
December 18, 2023: Look for Venus between the Scorpion’s claws in the southeast before sunrise. The thick crescent moon is in the evening sky with Jupiter and Saturn. - 2023, December 17: Celestial Pairs
December 17, 2023: Before sunrise, Venus passes Zubenelgenubi, a planet-star conjunction. After sundown, Saturn and crescent moon are paired, a planet-moon conjunction. - 2023, December 16: Venus Clawed, Evening Crescent Nears Saturn
December 16, 2023: Before daybreak, Venus is above the Scorpion’s southern claw. After nightfall, the crescent moon nears Saturn. - 2023, December 15: Brilliant Morning Star, Evening Lunar Crescent
December 15, 2023: Before sunrise, brilliant Venus approaches Zubenelgenubi, the Scorpion’s southern claw. The crescent moon returns to the western evening sky.
