Venus begins retrograde motion

Event Date: May 16th
Time: 8:00 PM

Brief

   Despite showing a local path in recent weeks for Venus, I have not shown a celestial path for quite some time; this is a good time for that, as Venus has started its retrograde motion.  This also means that separation between Venus and the Sun will quickly shrink, after being as much as 46º at greatest elongation back in March.  Notice the path here, and the 10-day increment markers.  The image is zoomed in 2x, to show the start of retrograde a little better.  As it continues, the markers will separate again, for if I remember to show the plot again in early June.  For now, the markers become closer together, as Venus reaches stationary.

click on image to enlarge: courtesy of Starry Night Pro Plus, version 6.4.3, by Simulation Curriculum Corp.

Detailed

   While still separated enough to see easily in the evening, daytime viewing of Venus will come to a fast end for a couple of months-- even when using an observatory.  After Venus retrogrades faster past inferior conjunction in June and comes out of the Sun's glare, we will beable to resume daytime viewing by mid-summer.  By that time, it will be separated enough to not only see easily; there will be less of a risk of accidentally sweeping the Sun with a telescope!
   When we see outer planets start retrograde, it means that we are catching up with that planet in our orbit; opposition isn't far away as well.  With Venus and Mercury as inner planets, it is the same, except they are catching up with Earth.  If a viewer was able to go to either planet and view Earth, opposition would happen at--or close to--the time that the planets are at inferior conjunction from our perspective: the Sun on one side of them, and the Earth 180º away.  Since the days on both inner planets are so many Earth-days, it means that a "fantasy" visitor would see Earth become a little brighter over a long span of time; during "night" on each inner planet.  Mercury rotates once every 59 Earth days, so it's night at the equator would be about one Earth-month.  Venus rotates even slower, at over 243 days (longer than its revolution!), so a night would be about four Earth-months.  If you ever want to experience this as a witness, get ahold of software such as the one I use here for imaging; most brands allow travel to other planets to view Earth.