by Jeffrey L. Hunt
Chicago, Illinois: Sunrise, 6:09 a.m. CDT; Sunset, 7:36 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:
Step outside about an hour before sunrise. Two bright planets are among the starry morning twilight festival of late August. A third is making its entrance at this hour.
Bright Jupiter is high in the south-southeast. It is 13.5° to the lower left of Hamal, Aries’ brightest star, and nearly 16° to the lower right of the Pleiades star cluster, part of Taurus. The Jovian Giant is moving eastward in front of Aries. The planet is slowing to begin its retrograde motion on September 4th.
Through a telescope with an 80x magnification eyepiece, the planet with the bright moons, Io, Europa, Ganymede, and Callisto, are to the west. The star Sigma Arietis (σ Ari on the chart) is west of the moons, nearly inline with the plane of their orbit, as if it were imitating one of them. The star is nearly 500 light years away and as Jupiter moves eastward forms a fixed spot to see the planet’s progress.
Saturn, nearly at opposition, is not as bright as Jupiter. The planet is low in the west-southwest, retrograding in front of Aquarius, 8.3° to the lower right of Skat, and 8.0° to the lower right of Lambda Aquarii (λ Aqr on the chart), nearly making an equilateral triangle with them.
At this hour, Venus is just above the east-northeast horizon. Look for it for the next fifteen to thirty minutes. It is higher in the sky, but twilight eventually washes it out as sunup nears. It is rising seven minutes earlier each morning compared to sunset.
Beginning next month, Venus and Sirius are nearly the same altitude – height above the horizon – before sunrise. Venus does not pass closely to the night’s brightest star, but the brightest planet and the brightest star are in the eastern sky at the same altitude for several days.
Through a telescope, Venus displays phases, like the moon, the “waxing” an “waning” names do not apply for the planet, because the phases occur in a different cycle from the moon. This morning, the phase is only 6% illuminated – a morning crescent phase.
Mercury and Mars are east of the sun. The innermost planet, sets only twenty-two minutes after the sun, heading for inferior conjunction – between Earth and the sun – and a stint in the morning sky.
Mars, dimmer than might be expected, sets about an hour after sunset and it is in a slow slide toward solar conjunction during November. It returns to the morning sky later next year.
The bright gibbous moon, 67% illuminated, is low in the south during the early evening, between Scorpius and Sagittarius, in front of Ophiuchus. The Scorpion is to the west of the moon with its bright star Antares, 13.1° to the right of the lunar orb. Sagittarius’ brighter stars resemble a teapot and take this unofficial name for some sky watchers.
With this bright moon, the stars are not easily seen. Use a binocular to trace Scorpius from Graffias and Dschubba, past Antares and finishing at the two stars at the tail, named Shaula and Lesath, nicknamed the “Cat’s Eyes.” Then locate the parts of the teapot to the east of the moon.
Saturn, one night from opposition, rises nearly at sunset. An hour later, the Ringed Wonder is nearly 10° up in the east-southeast. By midnight, it is about one-third of the way up in the south-southeast. At that hour, Jupiter is low in the eastern sky.
- 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.