Venus is that bright star in the western sky after sunset during May 2020. The brilliant planet Venus has a quasi-conjunction with the star Elnath on May 10, 2020.
Click here for our semi-technical description of the planets during May 2020.
A gallery of images of Venus approaching Elnath
YouTube video explaining the quasi-conjunction
During May, Venus approaches Elnath (β Tauri), the star the represents the Northern Horn of the Bull. The planet appears to move at a rate that carries it beyond the star – a conjunction. Venus seems to suddenly curve away from Elnath and move away from the star. This occurs during an interval lasting over two weeks. Because Venus moves within 5° of the star, this is called a quasi (near)-conjunction.
Here’s how to watch this unfold: About forty-five minutes after sunset, look westward. The gleaming “star” is Venus. Elnath is the dimmer star above Venus. A binocular may help you locate the star. On the first night on the chart, May 3, Venus is 2.6° to the lower right of the star.
The moon seems to vary sizes in the sky to our eyes, but some of these effects are illusions. In the sky we measure the sizes of objects by how large they appear to our eyes. This is measured in degrees as those on a protractor. The moon’s apparent diameter is about 0.5°, not as big as we might think. On the closest evening, the separation from Venus to Elnath is about three full moon diameters. It’s not a close passing, but one of noting, since Venus appears to make a sweeping left turn near the star as the planet seems to dive between Earth and sun.
During the next several evenings, watch as it closes in for its quasi-conjunction with Elnath.
On May 10, Venus is 1.4° to the lower left of Elnath.
Then Venus seems to make a sharp turn and pull away from Elnath.
By May 15, the gap is 1.8°. A few nights later (May 18) – the last evening plotted on the chart. Venus has moved 2.4° away from Elnath.
As this quasi-conjunction occurs, Venus appears lower in the sky each night. Early next month, Venus moves between Earth and sun (inferior conjunction) and reappears in the morning sky.
As Venus leaves the evening sky, Mercury appears for some fine views of the two planets together.
Read more about that here.
For a semitechnical description of the month’s planet activities, click here.
For more about Venus as an Evening Star, read this article.