Venus is creeping out into the great evening apparition of the type that – as Eric David reminded us in his comment – ends with a very close passage in front of the Sun: the close passage that produced the famous Venus transits of the past.
Here is how Venus appears above the sunset horizon over the whole of this evening apparition, as seen from latitude 40° north.
See the end note about enlarging illustrations.
The sunlit disks of Venus are exaggerated 480 times in size, otherwise they would all be dots too small to see. You can think of each as what you would see through your binocular or telescope.
And here is how the same scene will appear, very differently, from 35° south, a latitude roughly suiting Buenos Aires, South Africa, Australia, and New Zealand.
The dashed line is the celestial equator, which for northern locations slopes up leftward from the sunset horizon, rightward for southern locations. No other features, such as the Sun, stars, or the ecliptic, can be included, because in diagrams of this kind, based on altazimuth difference from the west point on the horizon, they are in different positions for every date. Venus is always on or near the ecliptic.
This type of apparition occurred 8 years ago, and 16, and so on, in the eight-year Venus cycle. And in those two previous incarnations it resulted in the transits. Here is the apparition that began eight years back from now.
The Venuses are at slightly different points along the path, because I choose to show them at days 1, 11, and 21 of each month. The path itself seems identical – on this small scale. But it isn’t quite. In June 2012 it crossed the northern half of the Sun. In June 2019, it will pass slightly farther north, missing the Sun. No more Venus transits, till they begin again with a very marginal one in 2117.
In this picture the Venus shapes are filled, instead of being outlines. I could use advice on which style you find clearer.
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ILLUSTRATIONS in these posts are made with precision but have to be inserted in another format. You may be able to enlarge them on your monitor. One way: right-click, and choose “View image”, then enlarge. Or choose “Copy image”, then put it on your desktop, then open it. On an iPad or phone, use the finger gesture that enlarges (spreading with two fingers, or tapping and dragging with three fingers). Other methods have been suggested, such as dragging the image to the desktop and opening it in other ways.
This weblog maintains its right to be about astronomy or anything under the sun.
PLEASE HELP ME UNDERSTAND THE MAJOR VENUS EVENTS ON THE SKY OVER TEOTIHUACAN AROUND 350-378 CE. What those major Venus events on the sky would be? Is there a place where I could set my viewer position and then ask for the (graph) position of Venus at Dawn/Dusk along a month or year of my selection?
The “filled” shapes are more true to life.
Huh. Eight years, one Venus cycle, since the 2012 transit of Venus that I witnessed from the west coast of Oahu with my kama’aina friends Cathie and Joyce. I wasn’t sufficiently tuned in to the cosmos to catch the 2004 transit, and I won’t be alive for the 2117 transit. But at least I saw the 2012 transit! By going to the drier lee shore of the island we had clear weather all day and were able to see the entire transit.
I prefer the outlines to the filled silhouettes. The outlines make it easier to distinguish Venus’ exact size and shape from the background sky.
By the way, Mercury will be transiting the Sun five weeks from today, on November 11, Veterans Day in the US, so I’ll have the day off from work. The transit will begin before sunrise here on the west coast of North America. If the weather is decent I’ll climb nearby Bernal Hill to see the Sun rise over the east bay hills and look for Mercury’s tiny dot through my little refractor with a solar filter.
I saw some of the the May 2016 Mercury transit from my backyard, through breaks in the clouds.
Thanks for maintaining the astronomical posts – and for the irregular notes on political and human rights issues. It is important to keep an eye on matters larger than our daily lives, with respect to nature as well as public affairs.
Regarding the depictions of planets and moons – my slight preference is for the filled images, but can also see that some instances may view better as outlines (such as eclipsing another object).
Abother matter about images, and more important than filled or outlined images: in most web posts that I read, images open as a separate image from the blog or document. I have no difficulty reducing and enlarging your graphics, but the entire document enlarges and reduces, not the graphic only.
However, since I do not work with web blogs and such, I can offer no help in how to achieve this, nor any estimation of trade-off between effort and benefit. If it is easy to cause the graphic to open separately, I would find it an improvement – but if this is complicated to achieve, don’t worry about it.
Still trying to get my head around the 290° right turn around May 1 on the 35 deg S map.
Another I’d like to see as image that includes the Venus-Moon conjunctions through this cycle.
I like them all and prefer the filled-in Venus shapes. Appreciate that you include the shapes. Thanks for all you do.