2023, September 13: Morning Planetary Jewels

Photo Caption – Venus, Mars, Regulus, September 25, 2017


by Jeffrey L. Hunt

Chicago, Illinois:  Sunrise, 6:29 a.m. CDT; Sunset, 7:04 p.m. CDT.  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, September 13: Venus, Sirius, Procyon, Regulus and the crescent moon are in the eastern sky before sunup.

Step outside an hour before sunrise this morning.  Bright stars and planets decorate the eastern and southern sections of the sky.  Brilliant Venus, this morning’s brightest starlike body, is over 20° above the eastern horizon.  Even while stepping toward the east, it appears higher in the sky each morning, gaining three minutes of rising time each day compared to sunrise.

Venus is moving eastward toward Regulus, Leo’s brightest star, over 17° to the lower left of the brilliant planet and about 10° above the horizon. Venus closes the gap to the star each morning, passing 2.3° from Regulus on October 9th.

Venus and Sirius, night’s brightest star, is about 40° to the right of Venus, in the southeastern sky at about Venus’ altitude – height above the horizon. Both bodies appear at nearly the same altitude throughout the month.

Sirius is too far away from the ecliptic, the plane of the solar system where the moon and planets appear to move through the sky, for a close conjunction of the star with the planets or moon.  We can admire the view of the brightest planet and brightest star in the eastern sky during morning twilight.

Procyon, meaning “before the dog” and also known as the Little Dog Star, is above an imaginary line from Venus to Sirius.  For sky watchers at mid-northern latitudes, it rises about 30 minutes before the Dog Star.

Chart Caption – 2023, September 13: Through a binocular the crescent moon and Regulus are visible.

Look for the moon, 2% illuminated, 4.7° to the lower left of Regulus. A binocular is helpful to see the scene. The pair is higher in the sky as morning twilight progresses toward daybreak.  So this is a balance between seeing the moon and Regulus in a darker sky or seeing them higher above any obstructions.

Photo Caption – Mercury as Never Seen Before. (NASA photo)

Mercury is racing into the morning sky, although it is not high enough to be seen during early twilight.  It rises nearly an hour before sunrise.  Twenty-five minutes later, it is about 4° above the eastern horizon, 7.4° to the lower right of the crescent moon.  The pair fits tightly into a binocular field of view, but Mercury is not very bright, likely washed out by brighter predawn light.

Chart Caption – 2023, September 13: Jupiter is high in the south-southwest during morning twilight.

At an hour before sunrise, bright Jupiter is high in the south-southwest.  Noticeably brighter than Sirius, but dimmer than Venus, the Jovian Giant stands against the stars of Aries, 13.5° to the lower left of Hamal, the Ram’s brightest star, and 11.2° to the upper right of Menkar, Cetus’ nostril.  Spot the Pleiades star cluster about 16° to the upper left of the planet.

Jupiter is retrograding, appearing to move westward compared to the distant starfield.  During the next several mornings, watch it move between Hamal and Menkar.

Photo Caption – Jupiter (NASA Photo)

At 2:21 a.m. CDT, when Jupiter is high in the southeast, the planet’s Great Red Spot is at the center of the planet in the southern hemisphere through a telescope.  This long-lived atmospheric disturbance returns to the center of the planet for sky watchers in the Americas, two Jupiter days later at 10:13 p.m. CDT when Jupiter is about 10° up in the eastern sky, viewed from Chicago.

Evening Sky

Photo Caption – NASA’s Hubble Space Telescope photographed Mars on July 18, 2018, during a dust storm and near its closest approach to Earth since 2003. (NASA photo)

Mars is slowly descending into bright twilight.  It is dimmer than expected, setting about an hour after the sun.

Chart Caption – 2023, September 13: During the early evening, Saturn is in the southeastern sky near Skat and Lambda Aquarii (λ Aqr).

Saturn is the western edge of the planet parade, rising in the east-southeast before the sun sets.  Two hours after nightfall, the Ringed Wonder is in the southeast.  Not as bright as dazzling Venus or Jupiter, it is brighter than most stars this evening.

Saturn retrogrades in front of Aquarius, 9.2° to the upper right of Skat, the Aquarian’s leg, and 9.5° to the right of Lambda Aquarii (λ Aqr on the chart).

During the night, the planet is farther westward, appearing in the south around midnight. Jupiter follows along about two hours behind Saturn. About two and one-half hours before sunrise, Venus, Jupiter, and Saturn are along the imaginary arc of the ecliptic from the east to the west-southwest.  By thirty minutes later, Saturn is near the horizon.

The Venus-Saturn opposition occurs October 10, when Saturn sets as Venus rises.  The two planets are 180° apart.  We do not see them in the sky at the same again until Venus is in bright twilight next March.


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