So where are Venus and Mercury?
Friday, 1 November, these two inner planets will be at one of their four respective and specific locations along their orbital path around the Sun relative to the location of the Earth along its orbital path around the Sun.
Firstly, the innermost planet, Mercury, is not in transit as the banner graphic at the top of the page suggests. However Mercury is between the Earth and the Sun as this graphic shows. And, for either Mercury or Venus, when that happens the inner planet is said to be at inferior conjunction, but not necesarily in transit, or crossing directly in front of the Sun. Because the orbital paths of the planets are inclined away from the plane of the ecliptic, or the Earth’s orbit, the two inner planets ‘behave’ more or less as our Moon does when it reaches new Moon phase. When these objects come between the Earth and the Sun they are more often than not above or below the plane of the ecliptic and are therefore not in transit or eclipse. This is because of the planets inclination to the plane of the ecliptic. There are only certain times when the circumstances for a transit of either Mercury or Venus. The most recent and basically the last for a long time, was the Venus transit of 2012. I went to Tucson Arizona to view the event. And with my sister-in-law we joined a small group of like-minded people to view the transit from the observatory on the summit of Mt. Lemmon.
The other inner planet, Venus, has reached the point in its orbit around the Sun where Venus is as far ‘out’ from the Sun as we see the two near the horizon. This is measured as the angle between the Sun, Venus, and the Earth. This animated graphic shows Venus above the horizon then crossfades to show Venus in its current orbital position. This orbital position is called an elongation, and since Venus is in the evening sky to the east from the Sun, and setting after the Sun, ‘we’ would say that Venus is at greatest eastern elongation. At this elongation Venus is 47.1 degrees from the Sun.
Click here to go to the Mercury Chaser web page to see the Mercury elongation calculator.
Click here to go to the Seeing Venus in the Daylight web page, then scroll down to see the Venus elongation calculator.
Click here to go to the Qué tal in the Current Skies web site for more observing information for this month.