April 9, 2023: Venus nears the Pleiades as Mercury reaches for greatest elongation in the western evening sky. Mars marches eastward in Gemini. Saturn is in the morning sky.
by Jeffrey L. Hunt
Chicago, Illinois: Sunrise, 6:20 a.m. CDT; Sunset, 7:25 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:
One hour before daybreak, the gibbous moon, 89% illuminated, is low in the south-southwest. It is approaching Dschubba, the Scorpion’s forehead. Later today, tomorrow morning in New Zealand, the moon covers or occults the star. This occultation is not visible from the Americas.
The lunar orb is over 10° to the right of Antares, the heart of Scorpius.
Saturn is visible at this hour in the east-southeast. Wait about 15 minutes for it to appear higher in the sky. At that time, the Ringed Wonder is nearly 10° above the horizon.
Saturn is not as bright as Venus or Jupiter, although it is among the brightest “stars” in the sky this morning. Each morning it rises a few minutes earlier and appears slightly higher than the previous morning.
Jupiter is two days from solar conjunction and a slow reappearance in the morning sky next month. This evening it sets only four minutes after the sun.
The planet show continues with brilliant Venus and Mercury. The Evening Star is the easiest to find, nearly 30° up in the west at 45 minutes after sunset. It is that “bright star” in the western sky that rivals the brightness of the lights on a low-flying airplane.
Venus is approaching the Pleiades star cluster, passing it tomorrow evening. This evening, the planet is 3.1° to the lower left of the stellar bundle. Notice Aldebaran, Taurus’ brightest star, over 13° to the upper left of Venus.
Through a binocular, Venus and the Pleiades comfortably fit into the same field of view. Count the number of stars you can see with and without the optical assistance.
Venus continues to step through Taurus, passing in front of interesting starfields. Use a binocular to track the planet against the sidereal backdrop.
Mercury is nearing its largest separation from the sun, known as the greatest elongation. With the plane of the solar system favorably tilted with the western horizon, the planet is easiest to see and highest in the sky at this time interval after nightfall.
Mercury is brighter than most of the starlike bodies in the western sky, except for Venus and Sirius. The speedy planet shines through the blush of evening twilight, so it may seem dimmer than other stars higher in the sky. Each night, as it reaches greatest elongation, it sets at its maximum time interval after sunset, it fades in brightness. In a week a binocular is generally needed to first find the planet, but this evening, it stands brightly about 10° above the west-northwest horizon, less than 20° to the lower right of brilliant Venus.
Mars is marching eastward in front of Gemini, to the upper right of Castor’s heel. The accompanying chart shows the Red Planet with the star pattern of two stick figures at about the end of evening twilight, when the sky is as dark as it is naturally. The dimmer stars that are visible are away from most urban and suburban settings. For most observers, Castor and Pollux are easy to see and possibly Alhena.
Mars is generally moving diagonally across the constellation toward Pollux. The planet passes the star in a wide conjunction on May 8th.
This evening, Mars is less than 40° to the upper left of Venus. The gap is closing between the two planets as Venus is slowly overtaking Mars. When does Venus catch Mars? Seems like one of those two train problems from Algebra class. Stay tuned for more details as the chase continues.
The moon rises over four hours after sunset, near the midnight hour.
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