2021, May 8: Watch the Planet Parade


May 8, 2021: Five planets are visible during morning and evening appearances.  Jupiter and Saturn are visible before sunrise.  Daylight interrupts the viewing until evening, when Venus, Mercury, and Mars are visible in the west after sundown.

Chart Caption – 2021, May 8: Jupiter and Saturn are in the southeastern sky before sunrise.

by Jeffrey L. Hunt

Chicago, Illinois:  Sunrise, 5:38 a.m. CDT; Sunset, 7:57 p.m. CDT.  Check local sources for sunrise and sunset times for your location.

Morning Sky

The planet observing morning session begins when Saturn rises nearly 4 hours before sunrise.  Bright Jupiter follows less than an hour later.

By one hour before sunrise, Jupiter is the “bright star” in the southeast, about 20° above the horizon.  The planet is moving eastward in front of the dim stars of Aquarius.  While the constellation is famous, its stars are faint.

Saturn is dimmer than Jupiter, but brighter than other stars in the immediate neighborhood.  In less than a week the planet begins to retrograde compared to the stars of Capricornus.

During retrograde motion, the planet appears to move westward compared to the sidereal background.  This illusion occurs when our faster moving planet overtakes and passes a slower moving outer planet.

Chart Caption – 2021, May 8: Thirty minutes before sunrise, the razor-thin moon is above the eastern horizon.

As twilight brightens the eastern morning sky, Jupiter and Saturn seem to appear farther westward.  By 30 minutes before sunrise, the crescent moon, 10% illuminated, is above the eastern horizon.

At sunrise, the moon and planets seem to disappear into the azure sky.  As the sun seems to move westward, Saturn, Jupiter and the lunar crescent set before sundown.

Evening Sky

Chart Caption – 2021, May 8: Brilliant Venus and Mercury are in the west-northwest, about 30 minutes after sunset.

As the sun sets and the sky begins to darken, brilliant Venus is low in the west- northwest.  Find a viewing spot with a clear horizon toward that direction. 

By 30 minutes after sunset, Venus is only 4° above the horizon.  At this time, Mercury is 8.5° to the upper left of Venus. A binocular may be needed to initially locate them.

Venus as an evening star article.

Read more about Venus in our summary document.

Chart Caption – 2021, May 8: By 45 minutes after sunset, Mars is visible to the upper left of Mercury. Venus is close to the west-northwest horizon.

Mercury is speeding into the evening sky, enroute to its best evening appearance of the year.  Each evening it is dimmer than the previous evening.

By 45 minutes after sunset, brighter stars are appearing and Mars is visible higher in the sky over 30° to the upper left of Mercury, now easily visible without optical help.

From that favorable viewing vantage point, Venus is just above the horizon.  Mercury is to Venus’ upper left, about 10° above the horizon, and Mars is to the upper left of Mercury. 

Here’s more about Mercury during May 2021.

Chart Caption – 2021, May 8: Mars is in Gemini below Castor and Pollux, 4.4° above Tejat Posterior (μ Gem) and 0.9° below Mebsuta (ε Gem).

By an hour after sunset, more stars are visible, although Venus has set and Mercury is lower in the west-northwest.

Mars is in Gemini, below Castor and Pollux.  This constellation somewhat looks like stick figures with their arms around the other’s shoulders as portrayed in the chart.  Mars is above Castor’s heel, Tejat Posterior (μ Gem on the chart).  The planet is below Mebsuta (ε Gem). 

In his 1944 article about star names and their meanings, George Davis wrote that Mebsuta’s name means “’the paw of the lion,’ i.e., the lion of the Arabs.”

Here’s more about Mars during 2021.

Venus sets nearly an hour after sunset, followed by Mercury about an hour later.  Mars sets over 4 hours after sunset.

Three evening planets and five planets total with Jupiter and Saturn in the morning sky.  The parade begins again tomorrow morning without the crescent moon.  Its nighttime face is toward earth.  The moon returns to the evening sky in a few evenings with Venus.

Detailed Note: One hour before sunrise, bright Jupiter is nearly 20° up in the southeast, with Saturn 16.0° to the Jovian Giant’s upper right.  Use a binocular to spot ι Aqr, 1.3° to the lower right of Jupiter, and θ Cap, 0.8° to the left of Saturn.  Thirty minutes later, the moon (26.5d, 10%) is over 5° above the east horizon.  During the evening three planets are visible.  Thirty minutes after sunset, Venus is over 4° up in the west-northwest.  Have you observed it without a binocular? Mercury (m = −0.5), over 12° up, is 8.5° to the upper left of Venus.  As the sky darkens further, Mercury is still 10.0° above the west-northwest horizon, 15 minutes later.  At this hour, use a binocular to spot Aldebaran and the Hyades star cluster to the lower left of the planet.  Mercury is 4.9° to the upper right of ε Tau.  In another fifteen minutes (one hour after sunset), Mercury is still over 7° above the horizon.  At this hour Mars is over 31° to the upper left of Mercury.  It is marching eastward in Gemini, 4.4° above μ Gem and 0.9° below ε Gem.  Note that Mars is nearly 14° below Castor.

Read more about the planets during May 2021.

2021, May 12: Spectacular Venus-Moon Grouping

May 12, 2021: Thirty minutes after sunset, the razor-thin moon is 1.2° to the left of brilliant Venus.  This is the closest grouping of the moon and Venus during this evening appearance of the brilliant planet.  Mercury is 9.1° to the upper left of Venus.  Mars maintains its eastward march in Gemini. Sirius and Aldebaran are near their heliacal settings, their final appearances in the evening sky for the year.

2021, May 12: Morning Planets Jupiter, Saturn

May 12, 2021: Before sunrise bright Jupiter, in front of Aquarius, is in the southeast before sunrise.  Saturn is to the upper right of Jupiter, in Capricornus.  In a few mornings, Saturn begins to retrograde.

2021, May 11: Planets March On

May 11, 2021: The planet parade continues today. Five planets are on display.  Bright Jupiter and Saturn are in the southeastern sky before sunrise.  After sundown, brilliant Venus, Mercury, and Mars are in the western sky.  The moon is at its New phase and at apogee today.

Categories: Astronomy, Sky Watching

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