September 2018

Four planets are visible in our evening sky this month. From west to east they are Venus, Jupiter, Saturn, and Mars. Mercury is a morning object when the month starts.

 

 

Venus is just below Spica at the start of the month. After reigning as a bright evening object for months, it is heading toward the sunset. The moon’s monthly pass by Venus is rather far from the planet this month. It’ll be 9.9° north of the planet on the 12^th. Venus is at aphelion 0.728 astronomical units from the sun on the 5^th.

 

Jupiter is moving eastward in the diamond of Libra. The moon passes 4.2° north of the planet on the 14^th.

 

Saturn is stationary over the teapot of Sagittarius. The moon is 2.1° north on the 17^th.

 

Mars is moving eastward from Sagittarius to Capricornus. The moon passes 4.8° on the 20^th. Mars is at perihelion 1.381 astronomical units from the sun on the 16^th.

 

Watch Mercury start the month between Cancer and Leo. By the 6^th, the planet is north of Regulus. The moon passes 0.9° north of Mercury on the 8^th. It keeps moving eastward and toward the sun. Mercury is at superior conjunction on the 21^st. Mercury is at perihelion 0.307 astronomical units from the sun on the 2^nd.

 

Neptune is at opposition on the 7^th. It’s 28.9 astronomical units from Earth.

 

Moon phases this month: last quarter on the 3^rd, new on the 9^th, first quarter on the 16^th, and full on the 25^th.

 

The moon’s orbital positions: northern lunistice on the 5^th, on the equator going south on the 11^th, southern lunistice on the 18^th, and on the equator going north on the 25^th. Perigee is on the 1^st at a distance of 361,300 km or 224,500 miles. Apogee is on the 20^th at 405,000 km or 251,600 miles.

 

Earth is at equinox at 01:55 UT on the 23^rd.