February 20, 2023: Hercules is visible before sunrise in the eastern sky. Venus moves to within 10° of Jupiter after sundown, while Mars marches eastward against Taurus.
by Jeffrey L. Hunt
Chicago, Illinois: Sunrise, 6:40 a.m. CST; Sunset, 5:30 p.m. CST. Check local sources for sunrise and sunset times for your location. Times are calculated from the U.S. Naval Observatory’s MICA computer program.
Jupiter’s Great Red Spot’s transit times, when it is in the center of the planet in the southern hemisphere: 2:01 UT, 11:57 UT, 21:53 UT. Convert the time to your time zone. In the US, subtract five hours for EST, six hours for CST, and so on. Use a telescope to see the spot. Times are from Sky & Telescope magazine.
The moon is at the New phase at 1:06 a.m. CST. It begins lunation 1239, the number of lunar cycles since the counting system started in 1923. Look for a thin crescent tomorrow evening to the lower left of Venus.
Here is today’s planet forecast:
Morning Sky
Without the moon or bright planets in the early morning sky, several bright stars are scattered across the heavenly vault. Vega, Altair, and Deneb are in the eastern sky, forming a large shape, known as the Summer Triangle.
Vega is the highest star of the three. Hercules, the Hero or Kneeler, is nearby – to the west. The pattern is about one-third of the way from Vega to Arcturus, that is high in the southwest.
Hercules’ stars are mostly dimmer than those in the Big Dipper and to see them, may require your eyes a few minutes to adapt to the darkness.
The famous part of the pattern is known as “the Keystone,” a wedge or keystone shape made of four stars. The shorter side is the waist of Hercules. He is upside down for northern hemisphere sky watchers.
The globular star cluster Messier 13 (M 13 on the chart) is along the western edge of the Keystone. Such stellar bunches revolve around the center of the galaxy outside the spiral arms. Mapping them helped astronomers determine the direction of the galaxy’s center and the approximate location of the sun relative to the galactic core.
Messier 13 is one of the best globulars for northern hemisphere sky watchers to spot. It is visible to the unaided eye, but nicely seen through a binocular as a fuzzy star that resembles a cotton ball. A telescope at lower powers brings it into a nice view.
While the cluster is approximately 25,000 light years away and contains hundreds of thousands of stars, it is about two-thirds of the moon’s diameter in the sky. It is relatively large, yet dim and fuzzy appearing.
Hercules’ shoulders are below the Keystone and end with Rasalgethe, meaning the “Kneeler’s Head.”
Look for this pattern each clear morning, or when it reaches the same location during early summer evenings. Anytime, look for Vega and Hercules to the star’s west.
Meanwhile, Mercury is retreating into bright sunlight. Spotting it is mostly a hopeless act. Rising less than 40 minutes before sunup, it is washed out by the approaching dawn.
Evening Sky
After sundown, the Venus-Jupiter show continues in the west-southwest. This evening Venus moves to within 10° of the Jovian Giant. Venus overtakes Jupiter on March 1st. From this evening through March 11th, Venus is within 10° of Jupiter, as it approaches, passes, and moves farther eastward.
At forty-five minutes after sundown, brilliant Venus is nearly 20° above the south-southwest horizon, 9.3° to the lower right of Jupiter.
Not to be outdone, Mars puts on its own exhibition, marching eastward compared to Taurus. Look high in the south-southeast at an hour after sundown, when the dimmer stars begin to appear as twilight fades.
This evening, Mars is 8.9° to the upper left of Aldebaran, the constellation’s brightest star, and 7.4° to the lower right of Elnath, the Bull’s northern horn. Mars passes the horn on March 9th.
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