2021, May 1: May Day’s Morning Planets, Jupiter and Saturn, Moon


May 1, 2021: Before sunrise, the bright moon is in the south above the handle of the Teapot of Sagittarius.  Morning planets Jupiter and Saturn are in the southeast.

Chart Caption – 2021, May 1: Through a binocular, the moon is above the star Phi Sagittarii (φ Sgr) in the handle of the Teapot Sagittarius.

by Jeffrey L. Hunt

Chicago, Illinois:  Sunrise, 5:47 a.m. CDT; Sunset, 7:50 p.m. CDT.  Check local sources for sunrise and sunset times for your location.

May Day is here!  Traditionally, the day was a celebration of the return of spring.  Trees have leaves and the flowers are blooming.  Be sure to put a may basket anonymously on a neighbor’s step or give one to your friend!

During this month, the five bright planets are visible during a 24-hour period.  Bright Jupiter and Saturn are visible during the morning, while Venus, Mercury, and Mars are evening planets.  This evening Venus and Mercury are a small challenge to locate, but they will soon break into a darker sky.

To see the morning planets, look to the southeast about an hour before sunrise.  First locate the moon.  Really you can’t miss it.  At this hour, the lunar orb – over 75% illuminated – will cast your shadow.  It is over 20° up in the south. 

Use a binocular to see it 0.4° above the star Phi Sagittarii (φ Sgr on the chart).  The star is part of the Teapot of Sagittarius.  With the binocular, in the bright moonlight, the star and the rest of the pot’s handle is visible.

Chart Caption – 2021, May 1: Bright Jupiter and Saturn are in the southeast before sunrise.

Morning planets Jupiter and Saturn are in the southeast.  Both planets are moving eastward compared to the sidereal background, Jupiter in Aquarius and Saturn in Capricornus. Both of them are less than one-fourth of the way up in the sky.

Jupiter is the bright “star” in the morning sky.  Saturn is 15.4° to the upper right of bright Jupiter.  The Ringed wonder is brighter than all the stars nearby, except Jupiter.

Detailed Note: Five planets are visible during the morning and evening hours, although Venus and Mercury are a challenge to see.  One hour before sunrise, the moon (19.3 days after the New phase, 76% illuminated) is over 20° above the south horizon. The lunar orb is 0.4° above Phi Sagittarii (φ Sgr, m = 3.2), a star in the handle of The Teapot of Sagittarius. Saturn (m = 0.7), above the southeast horizon, is nearly at the same altitude as the moon.  Jupiter (m = −2.2) is 15.4° of ecliptic longitude east of Saturn and to Saturn’s lower left.  Use a binocular to view Saturn 1.0° to the upper right of Theta Capricorni (θ Cap, m = 4.1), while Jupiter is 4.9° to the left of Deneb Algiedi (δ Cap, m = 2.8) and 1.4° above Iota Aquarii (ι Aqr, m = 4.3). The moon occults Nunki (σ Sgr, m = 2.0) as seen from Hawaii.  For more information see http://www.lunar-occultations.com/iota/bstar/0501zc2750.htm. The sun crosses the sky in a few minutes longer than 14 hours.  Morning Twilight and Evening Twilight total more than 3.5 hours.  Complete darkness occurs during 6.3 hours. Twenty minutes after sunset, brilliant Venus (m = −3.9) is over 4° up in the west-northwest.  Its theoretical first evening appearance occurred on April 19.  With a clear horizon, can you find it with and without a binocular?  Mercury (m = −1.1) is 5.2° above Venus. It is about 9° from the sun and at its brightness, the planet should be visible without a binocular.  As the sky darkens further, Mercury becomes visible, although it is lower in the sky. The planet is making its best evening appearance of the year, although each night it dims.  By 45 minutes after sunset, it is over 5° up in the west-northwest.  The Pleiades star cluster is above the speedy planet.  Mercury is 4.7° below Alcyone (η Tau, m = 2.8), the cluster’s brightest star.  Fifteen minutes later, locate Mars (m = 1.6) over one-third of the way up in the west.  It is moving eastward among the stars of Gemini, below Castor (α Gem, m = 1.6) and Pollux (β Gem, m = 1.2), the Gemini Twins.  This evening it is 2.3° to the upper right of Mu Geminorum (μ Gem, m = 2.8) and 5.0° to the lower right of Epsilon Geminorum (ε Gem, m = 3.0). As Venus emerges from bright twilight, it closes the gap with Mars leading up to their July 12 conjunction.  While not easily viewed together in the sky, the gap between them is nearly 44°.

Read more about the planets during May 2021.


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