2021, May 27: Impending Venus – Mercury Conjunction, Sirius Setting


May 27, 2021: Mercury approaches Venus the evening before a close conjunction of the two planets.  This is the closest visible grouping of the two planets until 2033, although over two dozen groupings occur during the interim.  Tonight is Sirius’ Cosmic Setting. It sets at sunset.  The moon is visible low in the southeast at three hours after sunset.

Chart Caption – 2021, May 27: Forty-five minutes after sunset, brilliant Evening Star Venus, Mercury, and Mars are in the western sky.

by Jeffrey L. Hunt

Chicago, Illinois:  Sunrise, 5:21 a.m. CDT; Sunset, 8:16 p.m. CDT.  Check local sources for sunrise and sunset times for your location.

This evening Sirius, sets at sunset.  The star sets 4 minutes earlier this evening.  While its setting does not coincide with sunset, this is the smallest interval between the setting of the sun and the star.  The difference is 2 minutes.  Sirius returns to the morning sky during mid-August.  That event is known as the heliacal rising.  This evening’s event is the cosmic setting.

Forty-five minutes after sunset, brilliant Venus is 5° above the west-northwest horizon.  Mercury, one day before its close conjunction with Venus, is 1.2° to the upper left of Earth’s Twin.

Chart Caption – 2021, May 27: Through a binocular, Mercury is 1.2° to the upper left of brilliant Venus. The star Elnath is 5.0° to the upper right of Mercury.

The planet might be visible with the unassisted eye, but a binocular is helpful to identify the illusive planet.  The star Elnath is 5.0° to the upper right of Mercury.

Tomorrow evening’s close conjunction is the closest of the two planets until 2033.  About 30 conjunctions of the planet duo occur in the interim.  One is very close, but it occurs near the sun and it is not visible under conventional means.

Mars is 26.5° to the upper left of Mercury to the lower left of Pollux, one of the Gemini Twins.  The Red Planet continues its eastward march through the constellation.

The bright moon is visible in the southeast about 3 hours after sunset.

Articles and Summaries.

Venus sets 80 minutes after sunset, followed by Mercury 5 minutes later.  Mars sets 199 minutes after sunset.

Detailed Note: One hour before sunrise, the bright moon (15.6d, 99%) is over 14° above the southwest horizon, 9.3° to the upper left of Antares.  Farther eastward, Saturn is less than one-third of the way up in the south-southeast.  Saturn is slowly retrograding in Capricornus, 0.6° to the right of θ Cap.  Saturn reversed its direction less than a week ago. Jupiter, moving eastward in Aquarius, is 17.7° to the lower left of Saturn. The Jovian Giant is the brightest “star’ in the region.  With the moon’s brightness, use a binocular to see this giant planet pair against the distant stars.  This morning, Jupiter is 2.5° to the lower left of ι Aqr, 4.2° to the lower right of θ Aqr, and 4.4° to the upper right of σ Aqr.  Sirius sets at sunset (With the star’s setting time changing 4 minutes each evening and the sun’s setting time changes a minute each day, this is the date with the shortest interval between sunset and star set, 2 minutes). During the early evening, Venus, Mercury, and Mars line up along a diagonal line.  Begin looking with a binocular about 30 minutes after sunset.  Brilliant Venus is nearly 8° up in the west-northwest.  Mercury (m = 2.0) is 1.2° to the upper left of Venus.  Fifteen minutes later, Venus is over 5° up, while Mercury is over 6° above the west-northwest horizon.  Note that Venus is 4.6° to the lower left of Elnath.  At this hour Mars is less than one-third of the way up in the west in front of the stars of Gemini.  By one hour after sunset, Venus is 3.0° up in the sky, while Mercury is about 4° in altitude.  In the darker sky, note that Mars is between δ Gem and κ Gem.  The Red Planet is 2.7° to the upper left of δ Gem, 3.3° to the lower right of κ Gem, and 5.8° to the lower left of Pollux.  Three hours after sunset, the moon (16.4d, 95%) is nearly 8° above the southeast horizon.

2021 – 2022, Venus – Mars Triple Conjunction

During 2021 into 2022, Venus passes Mars three times for a triple conjunction.  The first occurs on July 12, 2021.  The others occur during early 2022, followed by a close approach of the two planets.

2021, July 6: Venus – Saturn Opposition

July 6, 2021:  This is the second bright planet – planet opposition this month.  Venus and Saturn are in opposite directions from Earth.  Venus sets about the time that Saturn rises.  After this date, Venus and Saturn together are in the evening sky until early 2022.

2021, June 26 – June 30: Bright Moon, Morning Planets

June 26 – June 30, 2021:  The bright gibbous moon passes Jupiter and Saturn in the morning sky before sunrise.  Observe that the moon is in a different spot each morning, farther east toward the impending sunrise.

2021, June 15: Moon, Sickle of Leo

June 15, 2021:  The moon is with the Sickle of Leo this evening.  Step outside about an hour after sunset to find the crescent moon that is about 30% illuminated over one-third of the way up in the west.

Categories: Astronomy, Sky Watching

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