2021, April 18: Crescent Moon, Mars, Evening Sky

April 18, 2021:  The crescent moon is high in the west after sunset among the stars of Gemini, below Pollux and Castor.  Mars is above the Bull’s horns.  Daylight is 13 hours, 30 minutes long.

2021, April 18: During the early evening, the crescent moon is in the west below Castor and Pollux. Mars is above the Bull’s horns.
2021, April 18: During the early evening, the crescent moon is in the west below Castor and Pollux. Mars is above the Bull’s horns.

by Jeffrey L. Hunt

Chicago, Illinois:  Sunrise, 6:05 a.m. CDT; Sunset, 7:35 p.m. CDT.  Check local sources for sunrise and sunset times for your location.

The length of daylight has stretched to 13 hours, 30 minutes. Daylight continues to grow 2-3 minutes each day and another 31 minutes by month’s end.

Tomorrow evening, Venus makes its first evening appearance without the aid of a binocular or telescope. It’ll be very low in the west-northwest about 20 minutes after sunset. This evening Venus sets 30 minutes after the sun sets.

An hour after sundown, the moon, 38% illuminated, is nearly two-thirds of the way up in the west, with Gemini as the sidereal background.  It is 9.5° to the lower right of Pollux, one of the Twins. 

In a binocular, the lunar crescent is 4.8° to the lower right of the star Wasat, “the middle of the sky,” (δ Gem on the chart) and Mebsuta, “the outstretched paw of the lion,” (ε Gem) 4.6° to the lower right of the lunar slice.

The constellations that we recognize today have stars with names that are not associated with the celestial figure.  Those star names are associated with constellations of other sky watchers.

In an article printed in 1944, George Davis, Jr. connected the names of the stars with their meanings.  Regarding Metsuta, he wrote, “’the outstretched paw of the lion,’ i.e. the lion of the Arabs.”

Mars is to the lower right of the moon, above the horns of Taurus, Elnath and Zeta Tauri (ζ Tau).  The Red Planet is 4.3° to the upper right of Zeta Tauri.

In a few days, Mercury begins its best evening appearance of the year.  It is at superior conjunction, with the sun between Earth and Mercury, at 8:49 p.m. CDT.

Here’s more about Mars during 2021.

Read about Mars during April.

Detailed Note: One hour before sunrise, Jupiter is nearly 13° in altitude above the east-southeast horizon.  It is 3.2° to the upper left of Deneb Algiedi and 0.2° to the lower left of μ Cap.  Saturn is 13.9° to the upper right of Jupiter and 1.6° to the upper right of θ Cap.  One hour after sunset, the moon (7.0d, 38%) is nearly two-thirds of the way up in the west-southwest, among the stars of Gemini, 9.5° to the lower right of Pollux (β Gem, m = 1.2). Use a binocular to spot Wasat (“the middle of the sky,” δ Gem, m = 3.5) 4.8° to the upper left of the crescent and Mebsuta (‘the outstretched paw of the lion,” ε Gem, m =3.0) 4.6° to the moon’s lower right.  Mars – nearly 18° to the moon’s lower right – is above the horns of Taurus, 4.3° to the upper right of ζ Tau.  Mercury is at superior conjunction at 8:49 p.m. CDT.

Read more about the planets during April 2021.



Categories: Astronomy, Sky Watching

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