2023, May 17: Moon Occults Jupiter, Mars Marches into Cancer


May 17, 2023:  The crescent moon occults Jupiter across US, Canada, and Greenland.  Mars marches into Cancer.

Photo Caption – 2020, November 12: One hour before sunrise, brilliant Venus is 0.3° to the lower left of Theta Virginis (θ Vir) in the east-southeastern sky. The crescent moon is 6.5° above Venus and 2.9° to the lower left of Gamma Virginis (γ Vir).


by Jeffrey L. Hunt

Chicago, Illinois:  Sunrise, 5:29 a.m. CDT; Sunset, 8:06 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:

Morning Sky

Chart Caption – 2023, May 17: Jupiter, Saturn and the crescent moon are in the eastern sky before sunrise. Fomalhaut is above the southeast horizon.

Before sunrise, Jupiter and Saturn are on display with the crescent moon, 6% illuminated, in the eastern sky. Begin with Saturn, over 20° up in the southeast.  The Ringed Wonder continues to appear higher in the sky each morning.

The star Fomalhaut is making its first appearances in the morning sky at the mid-northern latitudes.  It is above the southeast horizon.

Chart Cation – 2023, May 17: During morning twilight, bright Jupiter and the crescent moon appear through a binocular.

The show of the morning is with Jupiter and the crescent moon, close together above the eastern horizon.  Find a clear view in that direction. The moon is 1.3° to the right of the planet and both nicely fit into the same binocular field or in the eyepiece of a spotting scope.

From across the U.S., Canada, and Greenland, the lunar disk occults or eclipses the Giant Planet. The lunar sliver is approaching the Jovian Giant for an occultation that begins an hour after sunrise in Chicago.  Jupiter reappears about an hour later.  Follow the pair with optical assistance as the sky brightens and continue to watch the occultation unfold after sunrise. For more westerly locations, the occultation begins earlier.

The link above lists cities across the area where the occultation is visible.  The list predicts Jupiter’s disappearance times as well as the reappearance times.  Scroll down the list to find U.S. cities.  The times are listed in Universal Time.  Subtract four hours for the Eastern Time Zone, five hours for Central Time, and one more hour for each successive western zone.

Evening Sky

Chart Caption – 2023, May 17: Venus and Mars stand in front of Gemini’s stars in the western sky near the end of evening twilight.

Brilliant Venus gleams in the western sky.  Simply described, it is “that bright star in the west.”  Forty-five minutes after sundown, it is about 30° above the horizon.  It is the brightest starlike body in the sky tonight, easily outshining all other stars.

Venus is stepping eastward against the Gemini Twins, 1.3° to the upper left of Mebsuta, also known as Epsilon Geminorum (ε Gem on the chart).  The planet is over 10° below Castor, one of the Twins.

Mars marches into Cancer this evening, over 15° to the upper left of Venus and 7.1° to the left of Pollux.

Mars continues to dim from the increasing distance to our planet.  The Red Planet was brightest when it was closest to Earth on November 30, 2022.  This evening the distance to Mars is over three times that closest separation.

Venus appears to be overtaking Mars in the sky, although on their orbital paths, Venus is slowly catching our planet.  The Evening Star passes between Earth and the sun during mid-August.

Return to the western view as the sky darkens further, about 90 minutes after nightfall, when the Twins’ dimmer stars are visible, making two side-by-side stick figures.

Watch the evening planets move eastward against the starry background.  During early June, Mars appears near the Beehive star cluster.  On the 2nd, it appears to be in the stellar bundle.



Leave a ReplyCancel reply