Tonight (June 11), just 38 hours after the Moon met the Sun to produce a “ring of fire” solar eclipse, our rocky satellite will connect to the second brightest object in the night sky: Venus.
As day turns into night, about 45 minutes after sunset tonight, take a look at the west-southwest sky for a beautiful celestial picture formed by a thin strip of crescent moon, only 3% illuminated, and the brilliant planet Venus. … Venus will hover just 4 degrees above and to the left of the Moon.
Venus-Moon pairs of this kind occur approximately monthly. To catch them together in the night sky again, check out the chart at the end of this article to see the schedule for the rest of this year.
Connected: Planet Venus: Ask Yourself About Venus Facts
Wanderings of Venus and the Moon
If Venus were stationary and did not move against the background of the night sky, then the meeting of Venus and the Moon would occur every 27 days, 7 hours and 43 minutes. This is called a “sidereal month,” or the length of time it takes for the moon to orbit the earth, using the stars in the background as a guide.
Since Venus and the Moon were close to each other on May 12, we could expect another close pairing last Tuesday (June 8) if the pair applied the “sidereal month rule.”
But Venus is not motionless. Like all other planets in our solar system, it moves in its own orbit around the sun. From our earthly point of view, Venus has shifted significantly to the east. Even on May 12, Venus was in the constellation Taurus, the bull. But tonight, the planet appears to have shifted nearly 40 degrees to the east, where it is currently in the constellation Gemini, Gemini.
If you raise your hand, your clenched fist at arm’s length is approximately 10 degrees. Forty degrees equals about four fists. Thus, the Moon had to travel much more across the sky to catch up with Venus. Since the moon appears to be moving across the sky at about 13 degrees per day, it needs three more days to catch up with Venus. This will take us to Friday night, where we will again see an attractive sight, although it will be quite low in our twilight skies in the west and northwest.
Night Sky, June 2021: What You Will See This Month [maps]
Orbital motion of the Earth taking into account
By the way, another factor that also needs to be considered is the movement of our own planet around the Sun. If you were looking for the crescent moon last Tuesday night, you would have to look up to the dawn sky to find – with difficulty – a thin waning crescent moon just two days before the new moon (and annular solar eclipse).
This is because during the 27 days that have passed since May 12, the movement of the Earth around the Sun could also cause the position of the Sun in the sky to shift to the east. In this case, right in the same common area that Venus and the Moon occupied on May 12th.
By tonight, however, the Moon will be far from the Sun and will be visible low in the west-northwest along with Venus. No other star or planet can come close to matching Venus in brightness, not even bright Jupiter, which appears above the east-southeast horizon this week.
Venus is so bright in the night sky that aircraft carriers sometimes mistook the planet for an enemy plane during World War II. There were even cases when Venus attracted anti-aircraft fire!
Return to 2013
Venus repeats its actions in an eight-year cycle, so this year’s image of the planet in the sky is an exact reproduction of 2013. The nature of each year of the cycle is determined by the time of the planet’s movement: in 2012/2020. the planet’s movement was very spectacular, including the passage of the Pleiades star cluster in 2020 and the rare passage of the Sun in 2012. However, for 2013/2021, they are relatively gray (when viewed from the Northern Hemisphere).
One feature of Venus this year is the fall to its southernmost declination at the beginning and another, more extreme, at the end. After Venus shone low in the east for early risers in January and February, Venus rose as the “Evening Star” in the second half of April. Standing slightly higher after each sunset in May and June, the planet is visible in the company of the planet Mercury and the stars Aldebaran and Pollux.
Its arch carries it lower than last year, and from July it stops rising. This is because it glides southeast, in front of the sun, through the stars of Cancer, Leo, Virgo and Libra. On November 5, the planet will be the southernmost in our sky. In fact, it hasn’t been that far south since 1930.
After that – during the last eight weeks of the year – Venus will finally rise to a fairly reasonable height above the west-southwest horizon by Thanksgiving and set almost 3 hours after sunset. However, shortly thereafter, he begins to glide across the sunset sky.
During the winter holiday season, it will become the equivalent of a “Christmas Star” shining like a beacon low in the west-southwest sky shortly after sunset. Finally, its next pass will be in front of the sun (and 5 degrees further north) on January 10, 2022.
|date||% moonlit||Separation of Venus and the Moon|
|11 july||6%||6 degrees|
|August 10||nine%||6 degrees|
|9th of September||13%||4.5 degrees|
|October 9||fifteen%||2 degrees|
|7 november||sixteen%||4.5 degrees|
|December 6||eleven%||3.5 degrees|
In the chart above, the first column shows the date, the second column shows the% illuminance of the crescent, and the third column shows the distance between the moon and Venus.
In my opinion, the two best sky observing opportunities (out of the six listed above) will come on September 9, when the Moon and Venus form a triangle with the nearby first magnitude blue star, Spica, and then on December 6, when Venus is almost directly above the moon. shining with the brightest light with a magnitude of -4.7 – twice as bright as it seems now! Both will look like a celestial holiday decoration gracing the low sky from west to southwest: the dazzling white light of Venus and the moon – with an earthy glow – mimicking a creepy-lit yellow and blue Christmas ball.
Joe Rao is an Instructor and Guest Lecturer at New York Hayden Planetarium… He writes about astronomy for Natural History Journalthen Farmers’ Almanac and other publications. Follow us on Twitter @Spacedotcom and further Facebook…