October 18, 2022: The thick crescent moon appears near the Praesepe star cluster and the celestial donkeys before sunrise. Overnight, Saturn leads Jupiter and Mars westward in the overnight planet parade.
by Jeffrey L. Hunt
Chicago, Illinois: Sunrise, 7:07 a.m. CDT; Sunset, 6:04 p.m. CDT. Check local sources for sunrise and sunset times for your location.
Here is today’s planet forecast:
The thick crescent moon, 43% illuminated, is high in the southeast during morning twilight. At an hour before sunrise, it is 10.1° to the lower left of Pollux. With Castor, the pair is the Gemini Twins.
The lunar orb is in front of Cancer’s dimmer stars, the large seemingly open space between Gemini and Leo. If the sky is dark enough, Asellus Australis – part of Cancer, meaning the southern donkey – is 7.4° below the moon.
Through a binocular, a second donkey – the northern one, Asellus Borealis, is visible. The donkeys might be eating from a manger – a star cluster known as the Praesepe or more commonly known as the Beehive star cluster.
The cluster has a stellar population numbering over 300 members. This stellar bunch and others like it occupy the spiral arms of the Milky Way. Likely the most famous galactic cluster is the Pleiades or Seven Sisters in Taurus.
The Beehive is about 500 light years away, one of the closest clusters to our solar system. The Pleiades are about 100 light years closer. Its stars are nearly 20 times brighter than those in the Praesepe cluster. When we look at them, the Pleiades are visible to the unaided eye, while the Praesepe resemble a fuzzy cloud that seems to be about twice the size of the moon.
Through the binocular, place the moon at the top of the view, the Praesepe is 5.4° below it with the northern donkey nearby. The other is outside the field of view.
The star cluster is the 44th entry on Charles Messier’s list of celestial objects that should not be confused with comets. His list has 110 entries. Interestingly, the Pleiades cluster is number 45. Over 30 Messier objects are in the sky this morning.
Bright Mars is farther westward at this hour. It is east of (above) an imaginary line from Elnath to Zeta Tauri, the Bull’s horns. Find the Red Planet high in the southwest. It is the brightest of the three reddish stars in the western sky that includes Betelgeuse and Aldebaran.
Mars is 2.2° to the upper right of Zeta Tauri. The planet is slowing to seemingly reverse its direction on October 30. Earth is quickly catching up to the planet to pass between it and the sun on December 7. The line of sight from Earth to Mars has been moving eastward against the starry background. As Earth overtakes Mars, the line of sight begins to shift westward. The result is that the Red Planet seems to move westward or retrograde compare to the starfield.
Yesterday, Mars passed between the horns. After retrograde begins, Mars passes between them again on November 13th.
Farther eastward at forty minutes before sunup, Mercury, brighter than Mars is less than 7° up in the east. It is quickly departing from its best morning appearance of the year. At this time, the low altitude and the glow of morning twilight might make its initial identification challenging. A binocular is helpful to find it. Once the located, the planet is still visible without the assist.
Mercury is headed for its superior conjunction on the far reaches of its solar orbit on November 8th, followed by its entry into the evening sky.
At this time use the binocular to look for Arcturus, about 3° up in the east-northeast. It is making its first morning appearance or its heliacal rising. Can you see it without the binocular?
Venus is nearing its solar conjunction on the 22nd. This morning it rises only seven minutes before daybreak, too close to the sun for reasonable observation.
Evening planets Jupiter and Saturn are in the eastern sky after sunset. Bright Jupiter, outshining all other stars in the sky this evening, is over 20° up in the east-southeast. It is retrograding in front of Pisces’ dim stars for about another month.
Dimmer Saturn is nearly a third of the way up in the south-southeast in front of the stars of eastern Capricornus. It appears near Deneb Algedi and Nashira. The Ringed Wonder is retrograding and inching toward Iota Capricorni (ι Cap on the chart).
The star is bright enough to be seen in remote locations without bright outdoor lighting. Others need a binocular to see Saturn with the distant stars. Saturn is 0.6° from Iota this evening. In five evenings, Saturn ends retrograde and begins to move eastward again in the direction of Nashira and Deneb Algedi.
During the night Saturn leads the planet parade westward. Mars rises nearly three hours after sunset. By midnight, the three planets are strung along an arc from the east to the southwest.
- 2023, December 19: A Scorpion Fumble, Moon MidwayDecember 19, 2023: Before sunrise, Venus appears below the Scorpion’s claws. After sundown, the moon is nearly midway from Saturn to Jupiter.
- 2023, December 18: Pinched VenusDecember 18, 2023: Look for Venus between the Scorpion’s claws in the southeast before sunrise. The thick crescent moon is in the evening sky with Jupiter and Saturn.
- 2023, December 17: Celestial PairsDecember 17, 2023: Before sunrise, Venus passes Zubenelgenubi, a planet-star conjunction. After sundown, Saturn and crescent moon are paired, a planet-moon conjunction.
- 2023, December 16: Venus Clawed, Evening Crescent Nears SaturnDecember 16, 2023: Before daybreak, Venus is above the Scorpion’s southern claw. After nightfall, the crescent moon nears Saturn.
- 2023, December 15: Brilliant Morning Star, Evening Lunar CrescentDecember 15, 2023: Before sunrise, brilliant Venus approaches Zubenelgenubi, the Scorpion’s southern claw. The crescent moon returns to the western evening sky.