Venus and Regulus in the dawn

On August 17 or 18 you saw (if you were up early enough in the morning) a conjunction of the two brightest planets, Venus and Jupiter.

Venus, moving toward its passage behind the Sun on Oct. 25, has departed eastward from Jupiter and now passes close north of the star Regulus, the “little king”, 21st in brightness of the stars of the night sky.  But now Venus is lower down and closer (only 13 degrees) to the Sun, so managing to see this conjunction will be a feat.

Here is a diagram of the eastward scene three quarters of an hour before sunrise on September 5, as seen from Europe or North America. The line that cuts the horizon at the east point is the celestial equator. the other line is the ecliptic, along which the Sun and (less exactly) the Moon and planets move.140905VenRegulus

If you click on the diagram you should see it much larger.

The moment of the closest conjunction, when Venus and Regulus are less than 3/4 of a degree apart, is 18 Universal Time (Greenwich Time). This is in the afternoon in Europe and America, so they can be seen about as close together on either of the mornings of Sep. 5 or 6, Venus moving Sun-ward past Regulus.

It happens that Venus is almost simultaneously at its perihelion, that is, the closest point to the Sun in its seven-and-a-half month orbit. But this matters very little, because of all the planets Venus has the most nearly circular orbit.

Write a comment