by Jeffrey L. Hunt
Chicago, Illinois: Sunrise, 7:02 a.m. CDT; Sunset, 6:11 p.m. CDT. Check local sources for sunrise and sunset times. Times are calculated by the US Naval Observatory’s MICA computer program.
Today, the moon’s shadow races across the western hemisphere, first crossing the Oregon shoreline. The eastward-bound shadow moves across Nevada, Utah, Colorado, Arizona, New Mexico, and Texas before crossing the Gulf of Mexico to meet the Yucatan Peninsula. The track parallels the coast of Central America, crossing into South America at Columbia, then making a hard eastward turn across Brazil to meet the Atlantic Ocean. Sky watchers in the shadow’s path see an annular or ring eclipse, today commonly known as a “ring of fire” eclipse.
Such eclipses occur when the moon is near its most distant point from Earth, called apogee, so that the lunar disk is not large enough to fully-cover the sun. The eclipse occurs about three and one-half days after the moon is at this far point. At the eclipse’s peak, a ring or annulus of light surrounds the moon.
Sky watchers outside the main shadow experience a partial eclipse, depending on their distance from the main shadow. For sky watchers in Chicago, the moon covers 54% of the sun, while 85% is covered from Phoenix.
The best way to observe the eclipse is by projecting the sun through a telescope or binocular to a screen.
Another way is to use a small hole, such as one poked through aluminum foil. When sunlight passes through the aperture, it makes an image of the eclipse on a white screen.
Overlapping leaves on a tree create natural pinholes projecting many eclipse images on the ground beneath the tree.
This eclipse is a precursor to the April 8, 2024, total solar eclipse that is visible across a large swath of North America. Historical weather is not promising for a clear day, although April 8, 2023, was clear across a large part of the eclipse path at eclipse time.
Next year’s eclipse occurs less than one day after the moon is at perigee, the closest point to Earth. The moon is large enough to fully cover the solar disk to reveal the sun’s corona.
Summaries of Current Sky Events
Summary for Venus as a Morning Star, 2023-24
Here is today’s planet forecast:
Two bright planets put on a show in the sky before daybreak on this eclipse morning. One hour before sunrise, brilliant Venus is over 30° above the east-southeast horizon, 4.9° below Regulus, Leo’s brightest star. The Morning Star continues its eastward trek in front of the distant stars.
Venus’ eastward change is easy to see from morning to morning. The planet is approaching Rho Leonis, ρ Leo on the chart. Look at the scene with a binocular. Venus, Regulus, and Rho snugly fit into the same binocular field of view. Rho Leonis is 2.3° to the lower left of the planet. Venus passes the dimmer star in two mornings.
Farther westward at this hour, bright Jupiter is about 30° above the western horizon. The Jovian Giant continues to retrograde in front of Aries, 12.5° to the left of Hamal, Aries’ brightest star, 11.2° to the upper right of Menkar, Cetus’ nostril, and over 18° below the Pleiades star cluster, part of Taurus.
Jupiter is slowly approaching an imaginary line from Hamal to Menkar. It lines up with the two stars on the 28th.
Technically, Mercury is in the morning sky, but it rises only twenty-two minutes before the sun. It is not easily visible.
Mars is not visible, setting twenty-eight minutes after the sun, and like Mercury, is lost in the sun’s glare. It reaches solar conjunction November 17th.
The third bright planet is Saturn, although it is not as dazzling as Venus or Jupiter. An hour after sundown, the Ringed Wonder is nearly 30° up in the southeastern sky. It is retrograding in front of Aquarius, 7.0° to the left of Deneb Algedi, Capricornus’ tail.
During the night as the wheel of the sky turns westward. Saturn is south over three hours after sundown. It sets in the west-southwest over four hours before daybreak and before Venus rises.
Jupiter rises fifty-eight minutes after sunset and it is theoretically visible an hour after sunset when sky watchers look for Saturn. An hour later, the Jovian Giant is over 10° up in the eastern sky. As the calendar day ends, the planet is over halfway up in the east-southeast. By tomorrow morning, it is again in the western sky.
- 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.