During the year, most the activity of the bright planets occurs in the evening sky. Mercury makes three evening appearances. During the first, it passes Jupiter and Saturn after the Great Conjunction. Venus appears in the western, although it sets before the end of twilight until later in the year. The brilliant planet has conjunctions with Mercury and Mars.
Several groupings occur with the moon and they are indicated on the chart.
Take note of the grouping of moon with the moon and planets in the western sky during June and July.
A challenging attempt to see five planets and the moon occurs on August 18. Mercury appears in a difficult-to-observe apparition and has a conjunction with Mars. Venus is higher in the sky while Jupiter and Saturn are in the eastern sky. The moon is present as well.
Mars leaves the evening sky later during the summer. The year ends with four planets – Mercury, Venus, Jupiter, and Saturn in western sky.
The chart above shows setting of the naked-eye planets, moon, and bright stars near the ecliptic for 2021. The graphs display the rising of these celestial bodies compared to sunrise and sunset for time intervals up to five hours before the sun’s appearance. The three phases of twilight are displayed as well. On the setting chart, activity occurs in the western sky, except for the rising curves (circles) of Jupiter and Saturn.
It should be noted that when two objects set at the same time intervals after sunset (same clock time), they are not necessarily near each other. It merely means that they rise or set at the same time interval after sunset. Since the charts feature objects’ activities near the ecliptic, they are likely to be up to 10° apart.
The charts are calculated from data by the U.S. Naval Observatory, for Chicago, Illinois.
April 21, 2021: Evening Star is making its first appearance in the west-northwest shortly after sunset. The gibbous moon is near Leo, while Mars is near the foot of Castor.
April 21, 2021: Jupiter and Saturn are the bright morning planets in the southeast before sunrise. The stars are in front of the backdrop of Capricornus. The constellation looks like an oversized boomerang or stealth fighter.
April 20, 2021: Venus is very low in the west-northwest after sunset. The gibbous moon is in Cancer, between Regulus and Pollux. Mars, above the horns of Taurus, approaches the star cluster Messier 35.
April 20, 2021: Bright Jupiter and Saturn are in the southeastern sky before sunrise, gently moving eastward compared to the starry backdrop of Capricornus.
April 19, 2021: The first evening appearance of Venus for this apparition occurs this evening. Look for it low in the west-northwest about 20 minutes after sunset.