2023, August 20: Morning Bright Stars, Evening Moon


August 20, 2023: Several bright stars, including Sirius, are in the eastern sky before sunrise.  The crescent moon is near Spica after sunset.

Photo Caption – The Crescent Moon, November 16, 2020


Jeffrey L. Hunt

Chicago, Illinois:  Sunrise, 6:04 a.m. CDT; Sunset, 7:44 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

Here is today’s planet forecast:

Morning Sky

Chart Caption – 2023, August 20: Bright stars, Sirius, Procyon, Betelgeuse, Rigel, Castor, and Pollux, are near the eastern horizon before sunrise.

An hour before sunrise, Sirius is clearing the east-southeast horizon.  After its heliacal rising at Chicago’s latitude on the 12th, the Dog Star appears earlier each morning.  Notice the other stars near the horizon, such as Orion’s Betelgeuse and Rigel. Gemini’s Castor and Pollux, are in the east-northeast, while Procyon, the Little Dog Star, is low in the east, to the upper left of Sirius. Jupiter is high in the southeast, above the horizon’s bright stars. 

Chart Caption – 2023, August 20: Jupiter is high in the southeast, moving eastward to the lower left of Hamal, Aries’ brightest star.

As Venus enters the morning sky, the Jovian Giant’s reign as the morning’s brightest star is ending. Jupiter is slowly moving eastward in front of Aries, 13.3° to the lower left of Hamal, the constellation’s brightest star and 11.3° to the upper left of Menkar, a star in Cetus.

Chart Caption – 2023, August 20: Through a telescope, Sigma Arietis (σ Ari) imitates one of Jupiter’s brightest satellites.

Through a telescope, the star Sigma Arietis (σ Ari on the chart) imitates a new bright Jovian satellite.  It appears far behind the orbital plane of Jupiter’s four brightest moons.  This morning it appears to the lower left of Europa. As Jupiter moves eastward, the star seems to revolve westward.

Photo Caption – Jupiter (NASA Photo)

At 2:31 a.m. CDT, Jupiter’s Great Red Spot is visible at the center of the planet through a telescope, when the planet is about 40° up in the east-southeast.

Chart Caption – 2023, August 20: Saturn is in the southwest before sunrise.

During morning twilight, Saturn is over 15° above the horizon in the southwest.  It is retrograding in front of Aquarius, 8.0° to the right of Skat, and 7.6° to the lower right of Lambda Aquarii (λ Aqr on the chart).

2020, June 14: The crescent Venus appears low in the east-northeast, 25 minutes before sunrise. Welcome back, Venus!

Venus is racing into the morning sky, rising thirty-five minutes before the sun. From a spot with a clear east horizon, the planet is about 3° up at twenty minutes before daybreak.  Theoretically, the planet is visible at this altitude – height above the horizon – and time before sunrise. In two mornings, the planet is higher during morning twilight and easily visible.

Evening Sky

Mercury, immersed in bright evening twilight, is rapidly moving toward inferior conjunction between Earth and the sun on September 6th.

Mars, slowly sliding into bright twilight, is dim and mostly a lost cause for observing without a bright celestial landmark for reference.

Chart Caption – 2023, August 20: The moon is in the west-southwest, near Spica, after sunset.

An hour after sundown, the crescent moon, 18% illuminated, is about 10° above the west-southwest horizon.  It is 5.9° to the right of Spica, Virgo’s brightest star, and 8.7° to the left of Porrima.

Photo Caption – 2023, May 22: Brilliant Venus and the crescent moon, with earthshine,

Look for earthshine on the night portion of the moon between the moon’s cusps or horns.  This effect is reflected sunlight from Earth’s oceans, clouds, and land.  Capture the scene with a tripod-mounted camera and an exposure lasting up to a few seconds.

Chart Caption – 2023, August 20: An hour after sunset, Saturn is about 10° above the east-southeast horizon.

At this hour, Saturn is nearly 10° above the horizon.  Opposition is less than a week, when the planet rises at sunset.  This evening Saturn appears at the horizon, seventeen minutes after sundown.

Jupiter crosses the eastern horizon less than three hours after sunset.  By tomorrow morning the planet is high in the southeast.  



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