by Jeffrey L. Hunt
Chicago, Illinois: Sunrise, 7:20 a.m. CDT; Sunset, 5:48 p.m. CDT. Check local sources for sunrise and sunset times. Times are calculated by the US Naval Observatory’s MICA computer program.
Beginning tomorrow, darkness is longer than daylight. This is not to be confused with the equinox that equally divides daylight and nighttime. Daylight occurs when the sun is in the sky. Its length varies during the year. Its length is simply calculated by subtracting the sunrise time from the sunset time. By adding twelve hours to the sunset time makes the calculation easy. In some circumstances, it is necessary to borrow and hour, convert it to sixty minutes, and add it to the sunset’s minutes column to complete the calculation. Today’s length is ten hours, twenty-eight minutes.
Nighttime is when the sun is not in the sky, about twelve hours at the equinox. Today, the length is thirteen hours, thirty-two minutes. Subtract daylight’s length from twenty-four hours, borrowing an hour or 60 minutes to calculate the minutes value. Nighttime is longer than daylight.
For the statement, “darkness is longer than daylight,” needs further explanation. Nighttime has three phases, evening twilight when the western sky is illuminated after sunset, darkness, and morning twilight before the sun rises.
These articles rely on the US Naval Observatory’s MICA computer program for the values related to this description. It provides times for the beginning of morning twilight, sunrise, sunset, and end of evening twilight. By calculating the length of twilight during a day and then subtracting this value for night’s length, darkness is determined.
Darkness is when the sky is as dark is it gets naturally. The metaphors, such as “dark as midnight” and “darkest before the dawn” do not refer to nature. At the end of evening twilight or beginning of morning twilight, the sky is as dark as midnight.
So, beginning tomorrow, darkness is longer than daylight until February 10, 2024, for 102 days at Chicago’s latitude. Locations farther south have fewer days and those farther northward experience more days for this effect.
Summaries of Current Sky Events
Summary for Venus as a Morning Star, 2023-24
Here is today’s planet forecast:
During morning twilight, the bright gibbous moon, 97% illuminated, is over 30° up in the western sky. Through a binocular, the Pleiades star cluster, 3.5° above the lunar orb, and the moon appear in the same binocular field. While easier to see than the dimmer planets, the moonlight can wash out dimmer stars. Once you find the scene, then move the binocular upward slightly so the moon leaves the field and the star cluster is below the center of the view.
The moon passes 1.6° south of the star cluster at 10:30 a.m. CDT, long after it sets across North America.
Bright Jupiter is about halfway from the western horizon to the gibbous moon. It is retrograding in front of Aries, 11.8° to the lower left of Hamal and 11.7° to the right of Menkar. It appears to be passing between the two stars. Use a binocular to find Menkar.
Earth is between Jupiter and the sun in four mornings. Because the Jovian Giant and the central star appear in opposite directions in the sky, Jupiter is said to be at opposition. Jupiter rises at sunset and sets at sunrise. The planet is closest to Earth on these occasions that occur about every 400 days.
Farther eastward, brilliant Venus, rising at its maximum time interval before sunrise, is over 30° above the east-southeast horizon. It steps eastward in front of Leo, over 20° to the lower left of Regulus, Leo’s brightest star, and 11.9° to the lower right of Denebola, the tail. Venus passes Denebola in a wide conjunction in a few mornings.
Mercury and Mars set several minutes after sunset and they are not visible.
An hour after sundown, Saturn is over 30° above the south-southeast horizon. It retrogrades in front of Aquarius, 6.7° to the left of Deneb Algedi, Aquarius’ tail. Both fit into the same field of a binocular. The planet’s retrograde ends November 4th.
Farther eastward at this hour, bright Jupiter is less than 10° up in the east-northeast. Two hours after sunset, the planet is nearly 20° up in the east and over 25° to the upper right of the gibbous moon, 94% illuminated.
- 2023, December 26: Cold Moon, Venus, Jupiter, SaturnDecember 26, 2023: The Cold Moon is visible during the nighttime hours. Venus shines before sunrise while Jupiter and Saturn are visible after sundown.
- 2023, December 25: Telescope First Light, Bright PlanetsDecember 25, 2023: For sky watchers with new telescopes, here’s what to look at before dawn or after sunset.
- 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.