April 21, 2023: Before sunrise, Saturn is low in the east-southeast. After sundown, a razor-thin moon appears with Taurus and its Pleiades star cluster. Venus is nearby along with Mars.
by Jeffrey L. Hunt
Chicago, Illinois: Sunrise, 6:02 a.m. CDT; Sunset, 7:38 p.m. CDT. Check local sources for sunrise and sunset times for your location. Times are calculated by the U.S. Naval Observatory’s MICA computer program.
Summaries of Current Sky Events
Here is today’s planet forecast:
Saturn continues a slow entry into the morning sky in the east-southeast. Forty-five minutes before sunrise, the planet is nearly 15° above the horizon. While not as bright as Venus or Jupiter, it is among the brightest starlike bodies in the sky this morning.
Jupiter follows Saturn out of bright sunlight. After its conjunction with the sun 10 days ago, it rises only 10 minutes before our central star, gaining two minutes of rising time compared to daybreak. It makes its first morning appearance next month.
The crescent moon is visible in the evening sky tonight beneath Venus. At forty-five minutes after sundown, the Evening Star is nearly 30° up in the west, 7.9° to the upper right of Aldebaran, Taurus’ bright star and nearly 20° to the upper left of the moon.
The razor-thin crescent moon, 4% illuminated, is over 10° above the west-northwest horizon. It displays earthshine, reflected sunlight from Earth’s features that gently lights up the lunar night. Its gentle glow is visible to the unassisted human eyes, but helped with a spotting scope or binocular.
Through the binocular, the moon and the Pleiades star cluster appear together, although snugly. This is a pretty sight with or without an optical assist.
While the binocular is at hand, notice Venus against the starfield. This evening it is 1.3° to the upper right of Tau Tauri (τ Tau on the chart). During the past few evenings, the planet passed outliers of the Hyades star cluster.
The accompanying chart shows the star Epsilon Tauri (ε Tau). It is part of the star cluster that with Aldebaran makes a letter “V” outlining the Bull’s head. The star is at the top of the letter opposite Aldebaran.
Mercury is above the horizon at this hour, but nearly impossible to see. It is over 5° above the horizon and 8.8° to the lower right of the lunar crescent. With the brightness of stars in the Big Dipper, the blush of evening twilight washes out easy views of the planet.
Venus continues its eastward step through the constellation toward the Bull’s horns Elnath and Zeta Tauri. Mars was in this region recently.
This evening the Red Planet, over halfway up in the west-southwest, is over 30° to the upper left of Venus. Mars is under an arc made by Procyon, Pollux, Castor, and Capella. It is dimming rapidly, but brighter than Pollux.
Mars is marching eastward in front of Gemini’s distant stars, 10.4° to the lower left of Castor and 10.5° to the lower right of Pollux. Mars is approaching Wasat – meaning “the middle of the sky.” The planet is 5.1° to the lower right of the star.
Mars passes nearly 2° to the upper right of Wasat on the 30th, heading toward a wide conjunction with Pollux on May 8th.
- 2023, December 24: Morning Moon, Pleiades, Antares Heliacal RisingDecember 24, 2023: The moon appears near the Pleiades star cluster during the earlier morning hours. Antares is at its first morning appearance, known as the heliacal rising.
- 2023, December 23: Check out Planet Uranus, Pleiades near MoonDecember 23, 2023: Look for the planet Uranus and the Pleiades star cluster through a binocular during nighttime hours.
- 2023, December 22: Mercury at Inferior Conjunction, Bright Jupiter, Gibbous MoonDecember 22, 2023: Mercury is between Earth and Sun, known as inferior conjunction. Jupiter and the gibbous moon are celestial companions during nighttime hours.
- 2023, December 21: Winter Solstice, Great Conjunction Plus 3 YearsDecember 21, 2023: Winter begins in the northern hemisphere. Jupiter and Saturn are visible in the evening sky three years after their Great Conjunction.
- 2023, December 20: Morning Star, Evening Moon Nears JupiterDecember 20, 2023: Brilliant Venus is in the southeast before daybreak. After nightfall the gibbous moon nears Jupiter in the southeast sky.