2023, September 5: Uranus-Moon Conjunction, Morning Star

Photo Caption – Venus, Procyon, and Sirius, September 26, 2015


by Jeffrey L. Hunt

Chicago, Illinois:  Sunrise, 6:20 a.m. CDT; Sunset, 7:18 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 5: Jupiter and the moon are the southern sky during morning twilight.

An hour before sunrise, the gibbous moon, 65% illuminated, is high in the south, 9.7° to the upper left of bright Jupiter and 6.0° to the lower right of the Pleiades star cluster.  The bright moonlight may obscure the cluster, so use a binocular to see them easily.

The moon is nearing the morning half phase, known as Last Quarter.  This occurs tomorrow at 5:21 p.m. CDT, when the moon is below the horizon in the Americas.

Jupiter is retrograding in front of Aries, 13.6° to the lower right of Hamal, the constellation’s brightest star. At 5:44 a.m. the planet’s Great Red Spot, a long-lived atmospheric disturbance, is visible at the center of the planet in the southern hemisphere through a telescope.  With Jupiter rising earlier each night, the window lengthens to see the spot.  On some nights it is visible twice from the planet’s rapid rotation that is less than 10 hours.

Chart Caption – 2023, September 5: Uranus and the moon appear in the same binocular field of view along with Delta Arietis (δ Ari) and Zeta Arietis (ζ Ari).

Uranus is in the same binocular field with the moon this morning.  The bright moonlight and growing twilight make this view challenging.  Place the moon at the center of the field of view.  Uranus is at the five o’clock position in the field toward the edge of the view.  The planet is noticeably dimmer than Delta Arietis (δ Ari on the chart) and Zeta Arietis (ζ Ari).  The sky may darken a little by slightly shifting the binocular so the moon moves out of the top of the field.  This moves Uranus near the center.

Chart Caption – 2023, September 5: Venus, Sirius, and Procyon are in the eastern sky before daybreak.

Venus continues its grand entrance into the morning sky.  Its retrograde against the background stars ended yesterday, although it continues to rise six to seven minutes earlier each morning.  An hour before sunup, the Morning Star is nearly 15° up in the east.

Through a telescope, Venus displays a morning crescent phase that is 15% illuminated.  A tiny crescent is visible through a binocular if held steadily.

Notice Sirius, night’s brightest star, in the southeast and slightly higher than Venus.  It is too far away from the plane of the solar system, known as the ecliptic, for any bright planet to appear near it.  The Venus-Sirius gap is about 40°.  Beginning in about a week, Sirius and Venus are about the same altitude – height above the horizon – during morning twilight.  This occurs nearly the rest of the month.

Procyon, meaning “before the dog” because it rises about 30 minutes before Sirius at the mid-northern latitudes, is above an imaginary line from Venus to Sirius.

 Evening Sky

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

Mercury’s inferior conjunction occurs tomorrow.  By month’s end it races into the morning sky for its best predawn appearance of the year.

Photo Caption – 2007, December 1: Late winter in the northern hemisphere shows clouds above the northern polar cap and some above the southern cap. (NASA Photo)

Mars, setting less than an hour after sunset, is dimmer than might be expected and awash in the blush of evening twilight.

Chart Caption – 2023, September 5: Saturn is in the southeast during the early evening, near Skat and Lambda Aquarii (λ Aqr).

Saturn rises in the east-southeast before sunset.  Two hours later it is over 20° above the southeast horizon.  The planet is not as bright as Venus or Jupiter, but it outshines most of the stars tonight.  The Ringed Wonder is retrograding in front of Aquarius, 8.8° to the upper right of Skat, the leg, and 8.9° to the right of Lambda Aquarii (λ Aqr).

Chart Caption – 2023, September 5: Jupiter and the moon are in the east-northeast as the calendar day ends.

Jupiter rises less than three hours after sundown.  As the midnight hour approaches, the Jovian Giant is over 15° up in the east and nearly 20° to the upper right of the half-lit moon.  The Pleiades star cluster is less than 5° to the upper right of the moon.  A binocular helps to see the cluster in this moonlight.


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