2023, March 10: Spiked Moon, Evening Planets


March 10, 2023: The gibbous moon is near Spica before sunrise and later during the night.  Three bright planets – Venus, Jupiter, and Mars – shine from the western sky after sundown.

Chart Caption – 2023, March 10: The moon is near Spica before sunup.


by Jeffrey L. Hunt

Chicago, Illinois:  Sunrise, 6:11 a.m. CST; Sunset, 5:51 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.

Here is today’s planet forecast:

Morning Sky

An hour before sunrise, the gibbous moon, 92% illuminated is less than one-third of the way up in the sky, 2.6° to the upper right of Spica, the brightest star in Virgo.

To see the star, block the moon with your hand as you would to shield your eyes from the sun.

Mercury is still west of the sun, rising only three minutes before daybreak.  It lines up with the sun at superior conjunction on the far arc of its solar orbit in a week.

Saturn is still hidden in bright morning twilight, rising nearly 40 minutes before sunup.  It makes its first appearance in about 10 days at the time of the equinox.

Evening Sky

Chart Caption – 2023, March 10: Venus and Jupiter gleam in the western sky after sundown.

The Venus-Jupiter gap continues to widen in the western sky after sundown.  Begin looking for Venus about 45 minutes after the sun sets.  It is over 20° above the horizon, with Jupiter 8.7° to the lower right of the Evening Star.

The two brightest starlike bodies are within 10° through tomorrow evening.  To the unassisted human eyes, the planets look like the stars.  While Sirius is clearly the brightest nighttime star, like the sun, the planets shine as stars from reflected sunlight.

The name for the bodies, planet, has its roots in the Greek word πλανήτης (planḗtēs), meaning “wanderer.”  To the earliest sky watchers, everything in the sky was a star, such as the fixed stars of the constellations, the shooting stars (meteors), hairy stars (comets), and wandering stars (planets).  They recognized seven objects – sun, moon, Mercury, Venus, Mars, Jupiter, and Saturn – that moved compared to the patterns of constellations.  The planets appear as stars to unaided eyes, so our description of Venus and Jupiter appearing as the brightest starlike bodies is within that perspective of the early sky watchers.

This evening Jupiter sets less than two hours after sundown. Venus follows about 45 minutes later.

Chart Caption – 2023, March 10: An hour after sunset, Mars is nearly between Elnath and Zeta Tauri, the Bull’s horns.

Mars continues its eastward march in front of Taurus, passing Elnath, the northern horn, last night.  Tomorrow, it swaggers between the horns.

At one hour after sunset, the Red Planet is high in the south-southwest, 3.1° to the lower left of Elnath and 4.8° to the upper right of Zeta Tauri, the southern horn.

Mars continues to dim as Earth pulls away.  The planet is dimmer than Capella, high in the sky to the planet’s upper right, and brighter than Aldebaran, Taurus’ brightest star, over 15° to the lower right of Mars.

Chart Caption – 2023, March 10: Five hours after sunset, the gibbous moon is low in the east-southeast to the lower left of Spica.

The gibbous moon, 87% illuminated, rises about four hours after sunset.  An hour later, it is nearly 15° above the east-southeast horizon and 9.4° to the lower left of Spica.  Notice the distance the lunar orb moved since it was in the southwestern sky this morning.



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