2023, September 30: Moon Approaches Jupiter

2020, May 12: The moon joins the morning planets, The gibbous moon is 3.1° to the lower right of Jupiter and 6.1° to the lower right of Saturn. Mars is farther east.


by Jeffrey L. Hunt

Chicago, Illinois:  Sunrise, 6:46 a.m. CDT; Sunset, 6:34 p.m. CDT.  Check local sources for sunrise and sunset times. Times are calculated by the US Naval Observatory’s MICA computer program.

During September’s last day, daylight lasts eleven hours, forty-eight minutes.  During the month, sunlight shed eighty minutes.

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

Here is today’s planet forecast:

Morning Sky

Over three hours before sunrise, Venus rises with Saturn low in the west-southwest.  Saturn is challenging to see without a binocular’s optical assist.  The planet’s low altitude – height above the horizon – affects the visibility because of the atmosphere’s blurring and dimming effects that are easily observed with the rising and setting sun and moon.

On October 10th, Venus rises as Saturn sets and they are not in the sky at the same time until next year.

Chart Caption – 2023, September 30: Jupiter and the bright moon are in the southwestern sky during morning twilight.

One hour before sunrise this morning the bright moon, 99% illuminated, is nearly 25° up in the west-southwest and about the same distance to the lower right of bright Jupiter.  The lunar orb moves closer to the Jovian Giant during the next two nights.

Jupiter continues to retrograde in front of Aries, 13.1° to the left of Hamal, the Ram’s brightest star, and 11.2° to the upper right of Menkar, Cetus’ nostril. A binocular might be needed to see these stars in the bright moonlight.

Photo Caption – Jupiter (NASA Photo)

Earlier this morning at 1:21 a.m. CDT, Jupiter’s Great Red Spot is at the center of the planet in the southern hemisphere.

Chart Caption – 2023, September 30: Venus, Mercury, and Regulus are in the east before daybreak.

Farther eastward, brilliant Venus and Mercury put on a show above the eastern horizon.  At forty-five minutes before daybreak, the Morning Star is over 30° above the east-southeast horizon.

Through a telescope, Venus displays a morning crescent that is 36% illuminated. While the phase is growing, the word “waxing” is not used for Venus’ phases.

Venus is stepping eastward in front of Leo.  It passes Regulus, meaning “the prince,” October 9th.  Through a binocular the planet is 1.5° above the star Omicron Leonis (ο Leo on the chart).  Venus passes the star in two mornings.

Mercury continues its retreat into morning twilight after its best morning display of the year.  The planet is bright, but it is less than 6° above the eastern horizon.  It is easy to see from a location with an unobstructed view toward Mercury’s direction.

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 sets less than 40 minutes after sunset.  It is dim and not easily visible with this early setting time.

Chart Caption – 2023, September 30: One hour after sundown, Saturn is in the southeast with Aquarius, near Skat and Lambda Aquarii (λ Aqr).

An hour after sundown, Saturn is over 20° above the southeastern horizon.  It continues to retrograde – move westward compared to the background stars – in front of Aquarius, 10.0° to the upper right of Skat, the Aquarian’s leg, and 10.5° to the right of Lambda Aquarii (λ Aqr on the chart).

The Ringed Wonder appears farther westward during the night and low in the west-southwest as Venus rises tomorrow morning.

Chart Caption – 2023, September 30: Three hours after sundown, Jupiter and the moon are in the eastern sky.

The moon is rising at this hour in the east-northeast.  Two hours later, the lunar orb, 96% illuminated, is less than 25° up in the east and 13.2° to the upper right of Jupiter, over 15° up in the east. The Jupiter-moon distance has closed since this morning.  Look for their separation in the morning.

As the day ends, Jupiter, led by the moon, is in the east-southeast.  Tomorrow morning, they are in the southwestern sky.



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