February 17, 2023: Before sunrise a thin crescent moon is above the southeastern horizon. After sundown, Venus, Jupiter, and Mars are visible.
by Jeffrey L. Hunt
Chicago, Illinois: Sunrise, 6:44 a.m. CST; Sunset, 5:26 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: 4:30 UT, 14:26 UT; Feb. 18, 0:22 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.
Here is today’s planet forecast:
Morning Sky
This morning a lovely crescent moon is low in the southeast at 45 minutes before sunup. The moon is only 11% illuminated and stands about 5° above the horizon. Find a clear horizon in that direction.
This is the last morning during this lunar cycle to see earthshine on the moon’s night portion. Sunlight that reflects from Earth’s oceans, clouds, and land gently illuminates the lunar night.
During the past 24 hours the lunar orb moved eastward through the Teapot of Sagittarius to its upper right. It eclipsed or occulted two of the brighter stars. New Zealand sky watchers saw it cover Phi Sagittarii and Tau Sagittarii from the Indian Ocean region across central Africa.
The moon is at the New phase on the 20th at 1:06 a.m. CDT, beginning lunation 1239, the number of lunar cycles since 1923.
When the moon reappears as an evening crescent, it appears with Venus and Jupiter, making a pretty sight in the evening sky. Don’t miss it.
Mercury continues to slide into morning twilight. It rises 46 minutes before sunrise, about the time of today’s morning chart. By the time it is high enough to see easily, the light of approaching daybreak is brighter than the planet.
After yesterday’s solar conjunction, Saturn is technically west of the sun, but it is lost in the sun’s radiance. We will see it rise before the sun in about a month.
Evening Sky
Step outside about forty-five minutes after sunset. Brilliant Venus and Jupiter shine from the west-southwest. The Evening Star is over 15° above the horizon, with Jupiter 12.3° to its upper left.
Venus, after its superior conjunction on October 22, 2022, is slowly climbing into the evening sky. Jupiter is heading toward its solar conjunction on April 11th. On the starry background, Venus is overtaking the Jovian Giant. Venus steps eastward faster than Jupiter, moving slowly eastward in front of Cetus.
In three evenings, Venus moves to within 10° of Jupiter. On the evenings of the 21st and 22nd, the crescent moon joins them, making a picturesque scene.
Venus and Neptune are still in the same binocular field of view after their conjunction. The more distant planet is dim and awash in the blush of mid-twilight, making its sighting difficult. If you did not see it, try one more evening.
With Venus to the upper left in the field, at about the 11 o’clock position, Neptune is in the center of the field, 3.0° to the lower right of Venus. The chart shows Neptune brighter than it is in the sky. This is a challenging observation.
The third bright planet, Mars, is high in the south-southeast, above the congregation of winter stars. It is marching eastward in front of Taurus, 9.4° to the upper left of Aldebaran and 8.3° to the lower right of Elnath.
The Red Planet passes between the Bull’s horns on March 11th.
At 6:22 p.m. CST, when Jupiter is less than 30° up in the west-southwest, the planet’s Great Red Spot is center stage in the planet’s southern hemisphere through a telescope. At this appearance, Jupiter’s satellite Io appears slightly above the spot. Its shadow is farther eastward on the cloud tops.
Depending on the clarity of the sky, follow the Red Spot, Io, and the shadow until about 7:45 p.m. when Io moves from in front of Jupiter and the spot disappears from Jupiter’s rapid rotation. By then the planet is only 10° up in the sky from Chicago. Sky watchers in the western US can see the planet higher in the sky and in clearer air.
Opportunities to see Jupiter in clear air and in a darker sky are quickly ending for this planetary appearance. They improve when Jupiter reappears in the morning sky later in the year.
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