2023, July 16: Venus-Regulus Quasi-Conjunction


July 16, 2023: Venus is closest to the star Regulus after sunset tonight.  The planet does not pass the star, but a quasi-conjunction occurs.

Photo Caption – Venus, Jupiter, Regulus, June 23, 2015


by Jeffrey L. Hunt

Chicago, Illinois:  Sunrise, 5:30 a.m. CDT; Sunset, 8:24 p.m. CDT.  Check local sources for sunrise and sunset times for your location.  Times are calculated by the U.S. Naval Observatory’s MICA computer program.

Summaries of Current Sky Events

Here is today’s planet forecast:

Morning Sky

Chart Caption – 2023, July 16: Jupiter is in the eastern sky before sunrise.

Two bright planets, Jupiter and Saturn, and a razor-thin crescent moon are visible before sunrise.  Before looking for the moon, find the planets. 

Bright Jupiter is nearly 40° above the east-southeast horizon.  It is slowly moving eastward in front of Aries’ distant stars, 11.7° below Hamal, the constellation’s brightest star.  Jupiter begins to retrograde on September 4th.

Through a binocular, up to four of the largest satellites are visible.  This morning all four of them are to the east of the planet.  Jupiter’s cloud tops, whipped parallel to the equator from the planet’s rapid rotation, are visible through a telescope.  Its Great Red Spot is visible tomorrow morning from the Americas.

The star Menkar, the sea monster’s nostril, is visible 11.7° to the lower right of Jupiter.  The planet is about halfway from Menkar to Hamal.

Chart Caption – 2023, July 16: Saturn is in the southern sky during morning twilight.

Saturn, considerably dimmer than Jupiter, is about 40° up in the south-southwest. While fainter than Jupiter, it is among the brightest stars this morning.

The Ringed Wonder is slowly retrograding – appearing to move west against the starfield – in front of Aquarius, 7.0° to the upper right of Skat – meaning “the leg” – and 5.5° to the lower right of Lambda Aquarii (λ Aqr on the chart).  Through a telescope, the rings are easily visible and their shadow can be found on the cloud tops. 

Earth passes between Saturn and the sun on August 27th.  The planet rises at sunset, appears in the south around midnight, and sets in the west at sunrise.

Chart Caption – 2023, July 16: The razor-thin moon is low in the east-northeast during bright morning twilight.

The lunar crescent is a more challenging observation this morning.  Forty-five minutes before the sun rises, find it only 6.0° above the east-northeast horizon. The phase is less than 2% illuminated.  Use a binocular and find an unobstructed view toward that direction.

The moon passes through the New phase tomorrow at 1:32 p.m. CDT and then into the evening sky to join the evening planet traffic jam.

Evening Sky

Chart Caption – 2023, July 16: Venus, Mercury, Mars, and Regulus are low in the west during bright evening twilight.

Three planets are visible after sundown during bright twilight.  The easiest to find is Venus.  It is still in its interval of greatest brightness, shining through evening twilight shortly after night falls.  By forty-five minutes after sundown, the Evening Star is less than 10° above the west horizon.

Venus sets three to four minutes earlier compared to sunset each evening.  It is overtaking our world on a faster inside orbital path.  Tonight, the planet is less than 36 million miles away, about 150 times the moon’s average distance from Earth.

Chart Caption – 2023, July 3-24: Venus’ and Mars’ motions relative to the Regulus and the ecliptic are displayed. Planet, Regulus, and ecliptic plots by Starry Night Pro 7.

This evening Venus closes to within 3.5° of Regulus, the brightest star in Leo, to the upper left of the planet.  Venus does not pass Regulus until October when they are in the morning sky.  Tonight’s event is a near or quasi-conjunction, defined as when Venus’ closest approach is within 5.0° of the star.

Eight years from tonight, Venus repeats the same quasi-conjunction, but the separation is 4.9°.  Every eight years, nearly to the day, Venus appears near the same stars at the same time before sunrise or after sunset.

Tonight, Venus is veering away from Regulus and begins to retrograde in six nights.

Chart Caption – 2023, July 16: Venus, Mars, and Regulus are visible in the same binocular field of view.

Mars, 6.9° to the upper left of Venus, marches eastward away from the brilliant planet and the star Regulus.  At this level of twilight, a binocular is needed to see the Red Planet and Leo’s brightest star. Depending on the binocular’s optical characteristics, this is the last night that the three bodies fit into the same field of view. 

Mercury is entering the evening sky, setting one hour after sundown.  This evening, use a binocular to find it near the west-northwest horizon.  It is bright, but dimmed considerably by the filtering effects from the air and pollutants near the horizon.  The same occurs when the sun rises or sets, dimming and reddening the central star.

Chart Caption – 2023, July 16: Saturn is in the east-southeast at three hours after nightfall.

Saturn rises in the east-southeast about two hours after sundown.  An hour later it is about 10° above the horizon.

Continue to watch the planet traffic jam in the western sky after sundown.  In three nights, the moon joins the scene.



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