May 20, 2021: Evening Star Venus, Mercury, and Mars continue their planetary dance in the western sky after sunset. Begin looking for brilliant Venus about 30 minutes after sunset. Fifteen minutes later, Mercury and Mars join the ballet.
by Jeffrey L. Hunt
Three bright planets dance in the western sky after sunset. Part of the daily planet parade, the evening section features brilliant Venus as it makes its way into the evening sky. It’s been a slow dance as the planet leaves bright twilight after its conjunction with the sun on March 26.
Mercury, dimming in brightness and appearing lower each night, is coming off its best evening appearance of the year.
At 45 minutes after sunset, Venus is about 5° up in the west-northwest. Find a clear horizon toward that direction. A hillside or elevated structure may help.
Mercury is 7.0° to the upper left of Venus. By this time, the planet is visible to the unassisted eye, but a binocular may help to initially see the speedy planet. Venus and Mercury appear at opposite sides of the typical binocular field of view.
The star Elnath, “the one butting with horns,” is 3.6° to the upper right of Mercury. The star marks Taurus’ northern horn.
On May 28, Mercury passes very close to Venus.
Mars, marching eastward in Gemini, is over 25° to the upper left of Mercury.
Look each evening at about this time, as Mercury is lower in the sky and closer to Venus. By month’s end, Mercury is back in the sun’s glare and moving toward its inferior conjunction between Earth and the sun.
Farther eastward, the bright moon, is the lower right of Denebola, “the tail of the lion.”
Read more about the planets during May 2021.