2021, May 14: Planets on Parade

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May 14, 2021:  Five planets are on parade.  Bright Jupiter and Saturn are in the southeast before sunrise.  After sundown, brilliant Evening Star Venus, Mercury, Mars, and the lunar crescent are in the evening sky.

Chart Caption – 2021, May 14: Morning planets Jupiter and Saturn are in the southeastern sky before sunrise.

by Jeffrey L. Hunt

Chicago, Illinois:  Sunrise, 5:31 a.m. CDT; Sunset, 8:03 p.m. CDT.  Check local sources for sunrise and sunset times for your location.

Morning Sky

The morning section of the planet parade is visible in the southeast before sunrise.

The procession begins about four hours before sunrise when Saturn rises in the east-southeast.  Jupiter follows Saturn across the horizon less than an hour later.

By one hour before sunrise, bright Jupiter is 22.0° up in the southeast.  The planet is brighter than all the stars in the morning sky.  Only the sun, moon, and Venus are brighter.  On occasions when Mars is close to Earth, the Red Planet can outshine Jupiter.

Jupiter’s brightness is from its large size and its highly reflective clouds that return to space over 50% of the sunlight that reach them.  If the planet were closer to our world, it would be much brighter in our sky.

In comparison, Venus reflects over 70% of the sunlight that strikes its clouds.  It is earth-sized, but much closer than Jupiter, outshining all other nighttime stars and planets.

Saturn – 25.0° up in the south-southeast – is 16.6° to the upper right of Jupiter. Saturn is brighter than most of the stars in the morning sky, except for Jupiter, Vega, and Arcturus.

Saturn is nearly twice Jupiter’s distance.  The planet reflects about 50% of the sunlight that shines on it.  While not striking in the sky, like Venus, Jupiter, and Mars, when close to Earth, Saturn is a spectacular sight through a telescope.

Should the opportunity arise, take an opportunity to look at the planet through an astronomy enthusiast’s telescope.

Use a binocular to see the starfields behind the two planets this morning.

Jupiter is slightly above a line from Iota Aquarii (ι Aqr on the chart) and Ancha (θ Aqr), “the hip,” 1.6° to the upper left of the former and 4.9° to the lower right of the latter.

Saturn is in front of Capricornus, 0.6° to the right of Theta Capricorni (θ Cap).

The sun’s brilliance interrupts the parade.  Jupiter and Saturn lead the sun across the azure sky and they set during the daytime.  Venus, Mercury, Mars, and the crescent moon follow the sun.  They are visible after sunset.

Evening Sky

Chart Caption – 2021, May 14: Thirty minutes after sunset Evening Star Venus, Mercury and the lunar crescent are visible in the west-northwestern sky.

After sunset, brilliant Evening Star Venus is low in the west-northwest, about 5° up in the sky.  Mercury is putting on its best evening display of the year for mid-northern latitudes.  It is over 9° to the upper left of the brilliant planet.

Each night Mercury is dimmer than the previous evening.

The crescent moon, only 9% illuminated this evening, is over 13° to the upper left of Mercury

A binocular may be needed to initially locate the evening planets and the lunar crescent.

As the sky darkens and the stars peek through the twilight, look for Sirius in the west-southwest, and Aldebaran to the lower left of Venus.  This may be the last evening to see them without an optical assist from a binocular.

This is known as the heliacal setting – the last appearance of a star in the western evening sky.   Aldebaran returns to the morning sky next month and Sirius returns during mid-August. The first appearance before sunrise is known as the heliacal rising of a star.

Venus as an evening star article.

Read more about Venus in our summary document.

Chart Caption – 2021, May 14: Forty-five minutes after sunset, Venus, Mercury, the crescent moon, and Mars are lineup along the ecliptic in the western sky.

By 45 minutes after sunset, Venus is very low in the sky.  Mercury is now visible to the unaided eye about 9° up in the sky.  The crescent moon is to the upper left of Mercury, and Mars is over 13° to the upper left of the moon.

The four bright objects are lined up along the ecliptic, the plane of the solar system.  During the spring months, the ecliptic makes a high angle with the horizon, permitting our “best” views of Mercury.

Here’s more about Mercury during May 2021.

Chart Caption – 2021, May 14: An hour after sunset, Mars is about one-third of the way up in the west, 2.9° to the upper left of Mebsuta (ε Gem) and 4.0° to the upper right of Mekbuda (ζ Gem).

An hour after sunset, Mars is in Gemini to the upper left of the moon that is at the Taurus-Gemini border.

Mars continues its eastward march through Gemini.  This evening it is 2.9° to the upper left of Mebsuta, “the outstretched paw of the lion,” (ε Gem on the chart) and 4.0° to the upper right of Mekbuda, “the folded paw of the lion,” (ζ Gem).

Tomorrow evening the moon is near Mars.

Here’s more about Mars during 2021.

Find a detailed chart of the motion of Mars during the month here.

This evening, Venus sets 65 minutes after sunset.  Mercury follows about an hour later.  This evening and for the next two evenings Mercury sets at its greatest interval after sunset (118 minutes).  Mars sets nearly four hours after sunset, about 90 minutes before Saturn crosses the horizon to lead off tomorrow’s planet parade.

Detailed Note: One hour before sunrise, bright Jupiter is nearly 22° above the southeast horizon.  Saturn (m = 0.6) – 25.0° up in the south-southeast – is 16.6° to the upper right of the Jovian Giant.  In the starfield Jupiter is slightly above a line from ι Aqr to θ Aqr.  It is 1.6° to the upper left of ι Aqr and 4.9° to the lower right of θ Aqr. Saturn is 0.6° to the right of θ Cap. Three bright planets and the crescent moon are in the west after sunset. Beginning 30 minutes after sundown, locate brilliant Venus over 5° above the west-northwest horizon.  Use a binocular to locate Mercury (m = 0.1), 9.1° to the upper left of Venus.  The moon (3.3d, 9%) is 24.0° above the horizon. This might be the last date to locate Sirius (α CMa, m = −1.5) and Aldebaran (α Tau, m = 0.8) at the latitude of Chicago.  Sirius is about 3° up in the west-southwest at 42 minutes after sunset. At the same time, Aldebaran is about 3° up in the west-northwest, 6.3° to the lower left of Venus.  A Sky and Telescope article describes the circumstances of the heliacal rising and setting of Sirius. Fifteen minutes later, Venus is over 3° in altitude, and Mercury, 11.5°.  Mars is 13.6° to the upper left of the lunar crescent. By one hour after sunset, Venus has nearly set, while Mercury is 9.0° above the west-northwest horizon.  The speedy planet is 7.2° to the lower right of Elnath.  The lunar slice is 5.6° above Zeta Tauri (ζ Tau, m = 3.0).  Mars marching eastward in Gemini is 2.9° to the upper left of ε Gem and 4.0° to the upper right of ζ Gem. This evening and the following two evenings, Mercury is at its latest setting time interval after sunset, 118 minutes, setting at the end of evening twilight.

Read more about the planets during May 2021.

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.



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