2021, May 1: May Day’s Evening Star Venus, Mercury, Mars


May 1, 2021: Evening star Venus, Mercury, and Mars are in the western sky after sunset.  Venus and Mercury are visible during brighter twilight.  Mars is in Gemini below Castor and Pollux.

Chart Caption – 2021, May 1: Thirty minutes after sunset, Venus and Mercury are in the west-northwest. Mercury is 5.2° above brilliant Venus.

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.

Five planets are visible during a 24-hour period.  Evening star Venus, Mercury, and Mars are visible after sunset.  Jupiter and Saturn are in the southeast before sunrise, along with the moon tomorrow morning.

Look for Venus about 4° up in the west-northwest about 20 minutes after sunset.  It is bright enough to be see without a binocular, but you may need to look through one initially to locate it.  Bright Mercury is 5.2° above Venus.  Depending on the field of view of the binocular, you might be able to fit both in the same field of view.

Can you see them without a binocular?

As night falls, Venus sets and Mercury appears lower in the sky.  By forty-five minutes after sunset, Mercury is about 5° above the west-northwest horizon.

Read more about Venus in our summary document.

Chart Caption – 2021, May 1: An hour after sunset, Mars is in the west in front of the stars of Gemini.

An hour after sunset, Mars, one-third of the way up in the west, appears in the darker sky, near the feet of Gemini.  The Red Planet is 2.3° to the upper right of Tejat Posterior, “the heel, (μ Gem on the chart) and 5.0° to the lower right of Mebsuta, “the outstretched paw of the lion” (ε Gem).

Here’s more about Mars during 2021.

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.


Leave a ReplyCancel reply