December 5, 2023: Venus is one astronomical unit from Earth this morning, about 93 million miles, or the Earth’s average distance from the sun. Bright Jupiter and Saturn are visible during the early evening.
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by Jeffrey L. Hunt
Chicago, Illinois: Sunrise, 7:03 a.m. CST; Sunset, 4:20 p.m. CST. Check local sources for sunrise and sunset times. Times are calculated by the US Naval Observatory’s MICA computer program.
In Chicago, the sun sets at 4:20 p.m., the earliest sunset. This occurs through the 15th.
Summaries of Current Sky Events
Summary for Venus as a Morning Star, 2023-24
Here is today’s planet forecast:
Morning Sky
Venus and Jupiter are five mornings away from their opposition. Afterward, Jupiter sets before Venus rises. The two planets are visible in the sky at the same time. They are in the sky for a forty-minute window before the Jovian Giant sets in the west-northwest at three hours before daybreak. The two planets can shine through the haze at the horizon that dims and blurs celestial objects. Viewing from an elevated structure or hilltop, or from a site with an unobstructed natural horizon, both planets are visible at the same time until their opposition date. Set an early alarm.
Venus and Jupiter are again visible at the same time after their next opposition November 4, 2024. This occurs in the evening sky when they first become visible again at the same time.
An hour before sunrise, the thick crescent moon, 48% illuminated, is high in the southern sky, below Leo’s haunches. The lunar orb was at the Last Quarter phase several minutes before this calendar day began.
The moon is 7.3° below Chertan, meaning “the two small ribs” or “the lion’s mane,” and 11.2° to the lower right of Denebola, the tail. (Most of the star names’ meanings described in these articles are from a 1944 article by George A. Davis, Jr.)
Farther westward a backwards-question-mark pattern, commonly known as the Sickle of Leo, makes the Lion’s head. Regulus, the constellation’s brightest star, is at the bottom of the shape.
A binocular might be needed to see the pattern this morning. The moon’s phase is still bright enough to wash over the dimmer stars.
Brilliant Venus is farther eastward at this hour, about 25° up in the southeastern sky. The planet is one astronomical unit from Earth, mirroring Earth’s average distance from the sun.
The astronomical unit or AU was an invention of early astronomers to measure the distance of the planets from the central star. While they did not know the distance to the sun, they were able to determine the distance of the planets relative to the Earth’s distance of one AU, about 93 million miles. Like a light year that is 5.8 trillion miles long, the astronomical unit makes it easy to represent the planets’ distances from the sun. Jupiter averages 5.2 AU from the sun, while Neptune is 30.2 AU. The nearest star outside the solar system is less than 300,000 AU away.
This morning, Venus is 7.9° to the lower left of Spica. Venus passed the planet in a wide conjunction a week ago. It is heading toward Zubenelgenubi, over 14° to the lower left and over 10° above the horizon. Venus passes this star on the 17th.
Mars, 2.5 AU from Earth this morning, rises twenty-three minutes before the sun. It is too close to the sun for easy observing.
Evening Sky
Mercury is a challenge to see during evening twilight. At sunset, the speedy planet, 0.98 AU from Earth, is 10° above the southwest horizon. Thirty minutes later, it is over 6° above the horizon. It is bright, but there is no other bright star as a celestial reference to help with its location. Sometimes challenging observations can be assisted by slowly moving the binocular parallel to the horizon. Then tilt the binocular slightly higher and sweeping again.
Mercury sets seventy-six minutes after sunset. While the observing window is narrow and the planet is lower as the sky darkens, sweep the sky several times to find the planet.
By an hour after nightfall, Saturn – dimmer than might be expected – is in the southern sky. It is over 35° above the horizon. An easy check to verify the planet is to locate Fomalhaut, slightly dimmer, about 20° to the Ring Wonder’s lower left.
Saturn is slowly moving eastward in front of Aquarius, 10.6° to the lower right of Lambda Aquarii (λ Aqr on the chart), 10.1° to the upper right of Skat, the Aquarian’s leg, and 7.6° to the upper left of Deneb Algedi, Capricornus’ tail. Use a binocular to see the dimmer stars, especially when looking from locales with outdoor lighting.
Bright Jupiter is easily visible at this time, over 30° above the east-southeast horizon. The Jovian Giant is retrograding – appearing to move westward compared to the distant starfield – 11.4° to the lower right of Hamal, the Ram’s brightest star, and 13.7° to the upper right of Menkar, Cetus’ nostril.
Use a binocular to find the dimmer stars in urban and suburban settings. With the binocular look for the Pleiades star cluster, nearly 25° to the lower left of the Jovian Giant. In dark locations without an optical assist, six or seven stars are visible. A few dozen are visible through the binocular.
Topaz Aldebaran, Taurus’ brightest star, is about 14° below the Pleiades. With the Hyades star cluster, another fabulous view through the binocular, Aldebaran makes a sideways letter “V,” representing the Bull’s head.
During the night the planets are farther westward. Saturn is setting earlier each night. Tonight, it sets nearly six hours after sunset. With the early sunsets, this is before midnight. Jupiter is south less than five hours after sunset, setting tomorrow morning around three hours before daybreak, at the end of a short time window when Venus is visible low in the east-southeast. The moon rises after midnight and its in the southern sky during morning twilight.
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