October 24, 2022: Before sunrise, a challenging view of Mars and a thin crescent moon is possible. The bright outer planets – Mars, Jupiter, and Saturn – are looping compared to the distant stars.
by Jeffrey L. Hunt
Chicago, Illinois: Sunrise, 7:14 a.m. CDT; Sunset, 5:56 p.m. CDT. Check local sources for sunrise and sunset times for your location.
Here is today’s planet forecast:
Mars is the last bright planet in the sky before sunrise. It is high in the southwestern sky above the Bull’s horns, Elnath and Zeta Tauri.
The planet seems to be slowing its eastward march before it appears to reverse its direction in six nights and begin to retrograde.
Planetary motion confounded early astronomers. The effect of retrograde, motion when the planet seems to move westward compared to the sidereal background, was difficult to explain. When Earth was thought to be unmoving and at the center of the universe, the planetary models used a series of circles on top of circles to explain how the planets moved backwards.
Astronomers, who thought Earth is a planet that revolves around the sun like the others, saw a faster moving planet revolving closer to the sun than Mars, Jupiter, and Saturn. When our world overtakes the outer planets, they seem to back up. The line of sight from Earth to one of the bright outer planets is projected to the distant starfield and normally moves eastward from the combined orbital motions of Earth and the planet. When faster-moving Earth moves between the planet and the sun, the line of sight shifts westward, or retrogrades against the stars. Neither Earth nor the comparison world stop in their orbital paths.
For this second model to be fully verified, Earth’s motion around the sun had to be observed. This did not occur until precision telescopes and measuring devices were developed during the 19th century.
In the sky, while Mars seems to be slowing to start to retrograde against the distant stars, it is not about to reverse its orbital path. This is an illusion of motion and sight lines.
On the chart above, the sight lines are drawn from Earth to Mars and projected outward on dates when Mars seems to pass distant stars. Notice that the lines tilt counterclockwise or eastward on the chart. As Earth closes in for the December 7th opposition, the lines shift clockwise or westward. After January 2023, the lines shift eastward again.
In yesterday’s article, we stated that it was Mercury’s “last call” for this morning appearance. For those with a very clear and unobstructed view toward the eastern horizon, a very thin moon, 1% illuminated, is visible 1.3° above the planet at 35 minutes before sunrise. The planet is only 3° up in the sky, about 10° south of the east-cardinal point. This observation requires a binocular and a little persistence. It’s not an easy one. The moon is new tomorrow morning at 11:49 a.m. CDT.
Mercury is retreating into bright sunlight. It rises 54 minutes before daybreak, losing three to four minutes of rising time each morning. The planet is at its superior conjunction with the sun on November 8.
After Venus’ superior conjunction two days ago, the planet is slowly climbing into the evening sky, setting only four minutes after the sun this evening. This is a slow entry in the western sky. By mid-November, the planet gains 15 minutes of setting time.
As Venus emerges from bright sunlight, the bright outer planets – Mars, Jupiter, and Saturn – are slowly migrating westward for a five-planet display near year’s end.
Jupiter and Saturn are in the southeastern sky after sunset. Bright Jupiter gleams from the east-southeast as night falls. Each night it is higher in the southeastern sky at the same time. This evening, the Jovian Giant is south about five hours after sunset and before midnight.
By mid-November, the planet is over one-third of the way up in the southeast as night falls and it is south 3.5 hours after sunset. With earlier sunsets, the planet is in the south around 9 p.m. local time.
When Jupiter is in the southern sky during this cycle of the planets, Saturn is in the southwest and Mars is in the east-northeast.
This evening Saturn is about one-third of the way up in the south-southeast during the early evening. Not as bright as Jupiter, the planet is near two not-so-bright stars in eastern Capricornus – Deneb Algedi and Nashira.
The planet stopped retrograding yesterday. The line of sight, similar to the chart for Mars in the morning section, is slowly beginning to shift eastward again. There’s not much change in its place against the background stars for several days. Then the line of sight from Earth to the Ringed Wonder begins to shift quicker eastward again.
Jupiter continues to retrograde in front a dim starfield in Pisces. The line of sight from Earth to Jupiter is still moving westward.
- 2023, October 21: Three Bright Planets, First Quarter MoonOctober 21, 2023: Venus, Jupiter, and Saturn are easy to locate during nighttime hours. The First Quarter moon phase occurs this evening.
- 2023, October 20: Jupiter’s Double Shadows, Mercury at Superior ConjunctionOctober 20: After midnight, Jupiter’s moons’ shadows dance across the cloud tops. Mercury is at superior conjunction.
- 2023, October 19: Poured Moon, See Planet UranusOctober 19: Sagittarius seems to pour the moon into the sky this evening. Find Uranus with a binocular.
- 2023, October 18: Moon-Antares Conjunction, Bright PlanetsOctober 18, 2023: The moon is near Antares after sunset. Venus, Jupiter, and Saturn are in the sky during the nighttime hours.
- 2023, October 17: Scorpion MoonOctober 17, 2023: The crescent moon is with Scorpius during evening twilight. Venus and Jupiter gleam from the predawn sky.