2021, May 25: Evening Star Venus, Mercury, Mars

May 25, 2021: Evening Star Venus, Mercury, and Mars are in the western sky after sunset.  Mercury is coming off its best evening appearance of the year.  Mars is marching eastward in Gemini.  The bright moon is in the southeast during the early evening near the star Graffias.

2021, May 25: Forty-five minutes after sunset, Mercury is 8° to the upper left of Venus and 4.4° to the lower left of Elnath.
Chart Caption – 2021, May 25: Forty-five minutes after sunset, Mercury is 8° to the upper left of Venus and 4.4° to the lower left of Elnath.

by Jeffrey L. Hunt

Chicago, Illinois:  Sunrise, 5:22 a.m. CDT; Sunset, 8:14 p.m. CDT.  Check local sources for sunrise and sunset times for your location.

After sundown, three planets are visible in the western sky.  Evening Star Venus is first to appear about 30 minutes after sunset.  This evening it is about 8° up in the west-northwest.  It stands alone because of its great visual intensity.

Mercury is not far away, but a binocular is needed in this bright sky to see it, 3.3° to the upper left of Venus.

Mercury is ending its best appearance in the evening sky this year and moving toward the sun’s glare.  The planet is speedy and its brightness changes quickly.  Just a week ago, by 40 minutes after sunset, the planet was easy to locate without a binocular.  This evening, finding it without one is challenging.

In just three evenings, Mercury passes close to Venus, only 0.4° separate them in the sky.  This is the closest observable conjunction until 2033, although other conjunctions occur during the interim.

Tonight, use the binocular to spot Elnath, the northern horn of Taurus, 4.4° to the upper right of Mercury.

Mars continues its eastward march through Gemini, 6.4° to the lower left of Pollux.  The Red Planet is nearly 26° to the upper left of Mercury.

Once Mercury leaves the sky, Venus closes in on Mars for a conjunction on July 12.  Make observations each evening to watch the gap close.  Unlike the bright morning planets that seem to move slowly compared to the starry background, the gap between Venus and Mars closes quite quickly.

2021, May 25: Two hours after sunset, the bright moon is 3.2° to the upper right of Graffias, the second brightest star in Scorpius.
Chart Caption – 2021, May 25: Two hours after sunset, the bright moon is 3.2° to the upper right of Graffias, the second brightest star in Scorpius.

The bright, nearly-full moon is in the southeast during early evening.  It is 3.2° to the upper right of Graffias, “the crab,” the second brightest star in Scorpius.

The lunar orb reaches its closest point to Earth, perigee, at 8:50 p.m. CDT, when it is 222,061 miles away.  The perigee Full Moon occurs tomorrow during a lunar eclipse. 

The Old Farmer’s Almanac names this month’s Full Moon, the Flower Moon.  So many adjectives will likely fly around the news media that include “super,” “blood,” and “flower,” among others. Because writers like to invent new names for reasonably common celestial events, we may soon have another “supercalifragilisticexpialidocious” name for eclipsed full moons that occur near their perigee.

Articles and Summaries.

Venus sets 78 minutes after sunset, followed by Mercury less than 30 minutes later.  Mars sets 204 minutes after sunset.

Detailed Note: One hour before sunrise, Saturn – retrograding slowly in Capricornus – is less than 30° above the south-southeast horizon.  It is 0.6° to the right of θ Cap.  Bright Jupiter is 17.6° of ecliptic longitude to the east and lower left of the Ringed Wonder.  The Jovian Giant is 26.0° up in the southeast, 2.4° to the upper left of ι Aqr, 4.3° to the lower right of θ Aqr, and 4.6° to the upper right of σ Aqr.  The moon is at perigee (222,061 miles) at 8:50 p.m. CDT.  A perigee full moon with an eclipse occurs tomorrow morning. Three evening planets continue their display in the western sky after sunset.  As the sky darkens, the trio makes a diagonal line above the horizon. Thirty minutes after sunset, brilliant Venus – over a month after is appearance in the evening sky, is nearly 8° up in the west-northwest.  Use a binocular to locate fading Mercury (m = 1.6), 3.3° to the upper left of the brilliant planet. The nearly full moon (14.3d, 100%) is about 10° above the southeast horizon. By 45 minutes after the sun sets, the planet trio is visible to the unaided eye.  Albeit low, Venus is 5° above the horizon, and Mercury is nearly 8° up and to the upper left of Venus. Spot Elnath, 4.4° to the upper right of Mercury.  Mars – less than one-third of the way up in the west – is nearly 26° to the upper left of Mercury.  In the southeast, the moon is 3.2° to the upper right of Graffias (β Sco, m = 2.5).  An hour after sunset, Venus’ altitude is less than 3°, while Mercury is over 5° above the west-northwest horizon.  In the starfield, Mars is 1.8° to the upper right of δ Gem and 6.4° to the lower left of Pollux.  The setting time intervals for the planets this evening: Venus, 78 minutes (m) after sunset; Mercury, 95 m; and Mars, 204 m.



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