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Today we are going to be looking at Venus. In a recent video, when we were taking an overview of March, I pointed out Venus visible at sunset in the early part of March, really close to Mercury, and once we came around to the end of March I showed Venus at sunrise after coming around to the other side of the Sun. However, in between those extremes, we have a window where Venus is visible at both times, morning and evening.

We’ll begin with sunset on the 18th. Venus is going to be visible at sunset on the 18th, but it’s a little tricky. Venus is quite low to the horizon, just about visible above hills or short buildings. If your horizon is slightly clearer then of course you’ll be able to see Venus brighter and lower in the sky, but the atmosphere will begin to make Venus look fainter as it gets lower. The atmosphere will extinct Venus as it gets very close to the horizon.

We’ll go through the night and turn from the western sunset all the way around to the eastern sunrise. As usual, we are starting with a view from a city in terms of the amount of light pollution being assumed. With the assumed landscape in Guéreins in France, the eastern view is incredibly clear. The eastern horizon has nothing big or tall on it at all. The basic landscape in the Stellarium software is an image taken from slightly elevated position, some number of meters up from sea level. It just so happens that there is essentially nothing blocking the eastern view. I often complain about trees and buildings in the west because this landscape has a hill and a big tree in that direction. Even a lot of the other horizons, compared to the western one at least, are pretty clear, but the view east is close to perfect. Coming around to sunrise, and there’s Venus in the morning on the 19th. We saw Venus setting with the Sun and coming up with the sunrise.

It is not the case that Venus has moved from one side of the Sun to the other. It’s more a case of Venus being so far from the Sun thanks to the inclination of its orbit that we are able to see Venus at sunset and at sunrise. In fact, for two different observers on two different parts of the Earth, one of them could be looking at Venus at sunset while the other observes Venus at sunrise. It’s not that Venus moves from one side of the Sun to the other in the space of a night, of course it doesn’t. Venus is visible at sunset and at sunrise, at the same time, because of Venus’s position relative to the Sun.

By taking a look at the midday sky with the atmosphere turned off, we can see the Sun and Venus at the same time. With this view, we can see that Venus is way above, or north, of the Sun. Of course, the Sun is also really far away from us and Venus is much closer to us, so there is a little bit of an optical illusion going on in terms of distances. However, from our perspective, Venus is significantly above us and the Sun. Our orbit is also slightly inclined, it doesn’t exactly match the ecliptic. All of the planets have a little bit of variation of this kind. We generally follow the ecliptic, but there is usually some amount of deviation. It’s very similar to planets rotating. The poles of a planet normally point North-South, but in the case of the Earth for example, we’re tilted over 23.5 degrees. In the case of Uranus, it’s completely on its side and in the case of Venus it’s upside down, or at least it seems to be upside down.

The ecliptic is usually defined in a way that puts the Earths inclination at 0 degrees, but compared to the actual equator of the Sun, rather than a projection of it from the Earth, all of the planets are slightly inclined. With the ecliptic drawn across the atmosphere-less sky, it can be seen that Saturn is in fact quite close to the ecliptic, it’s going off of it by a small angle. Mercury is also quite close to the ecliptic, or at least appears to be right now. Venus appears quite high off the ecliptic, and moving back through time we can see that it comes out to the side of the Sun and lines up with the ecliptic when it was at its greatest elongation. Coming back to the 19th and it arcs up over the Sun from our perspective. The angle of Venus’s inclination and the angle of the Earth’s inclination are at play here, and it adds up to put Venus in this incredibly high position.

Venus was visible at sunrise on the morning of the 19th, and it will continue to be visible at sunset on the 19th, just barely. It is a little harder to see Venus at sunset on the 19th than it is on the 18th, and on the 18th it was already getting pretty hard to observe Venus from here in Ireland. The it will be quite low and with those hills that I mentioned, they’re going to get in the way while Venus is still pretty high off the horizon. Venus is still visible above those hills, but we can use the artificially flat zero horizon in Stellarium, which would show Venus staying visible for significantly longer. We needed that very clear view to the east to catch Venus just as it was rising on the 19th, and we may need it for the setting Venus by the 20th. The rising Venus will get easier and easier as we move through to the 21st and forward into the year. Venus will continue to get further and further to it’s western elongation, when we see it in the morning, as we move through April.

We will go to that zero horizon and hopefully I will get a chance to show what this might look like from some some other locations as well. From here in Ireland we’re pretty high up on the planet, so the angle at which we see things rising and setting can be a little bit steep. With the zero horizon we can see Venus a little bit longer. If you’ve got a clear enough view to the west, Venus should look really quite obvious. It remains very bright even against the glow of sunset. If we were in the countryside of course it would be even better, so we’ll the light pollution to simulate the countryside. IN true darkness we can definitely see Venus bright above the horizon. Mercury is also there, but pretty much impossible to see. Even though I it is higher above the horizon than Venus, it’s just so much fainter. Venus is that much brighter than Mercury that Mercury is pretty much not visible at all even though it is further from the sunset than Venus. Venus has that height above the Sun, but it only remains visible thanks to the angle of the sunset.

Moving the whole way through the night, at this particular point of the month the Moon is pretty much in Scorpius, so it’s going to block out a lot of the glow of the Milky Way. The Milky Way will get easier to see as we move out of March and into April. Of course we have the partial solar eclipse coming up at the end of the month and those only happen during the New Moon. During the New Moon, the sky will be nice and dark, and the Milky Way should get a bit more visible early in the morning, just before sunrise. At sunrise again, and there is Venus in the morning on the 20th, still absolutely visible in a zero horizon at least. In a zero horizon at least Venus should still be visible at sunset from Ireland on the 20th, but probably only with a very clear horizon. Even with a perfect horizon, on the 20th Venus is just visible just after the Sun goes down. Even on the 21st you might just catch it with a clear horizon and a dark sky. Of course it will be visible in the morning of the 21st and getting easier and easier moving forward.

Very quickly heading to sunrise and moving forward a little bit in time to April, we can see Venus are only getting further and further out from Sun. Mercury and Saturn will join just underneath Venus around the 1st of April, but they will be closer to the horizon from here in Ireland. If we go a little bit closer to the equator the view will change. From the equator, or really about 1 degree south but that’s close enough, from the equator this continues to work fine. Venus is visible nice and clearly in the east, and it’s much higher above the horizon by the time we’re into April. On April 1st, we can see Mercury and Saturn much more easily from the equator. It would be pretty tricky to see those three planets together from here in Ireland.

Moving back to the dates of the double Venus, first we lose Mercury and Saturn. and then we lose Venus as well. On the 21st it’s just about above the horizon but it’s very difficult to see. The angle that we’re seeing Venus at from here in Ireland makes it a little bit easier to see twice. With the atmosphere turned off, we can see that on the 19th the Sun and Venus are almost in line, perpendicular to the horizon. Moving through to sunset around to the west, the glow of the Milky Way is clearly visible, but this is with the atmosphere turned off, that’s why the Moon isn’t blocking out the glow of the Milky Way quite as much. Coming up tp the sunset and Venus is goes under the horizon as the Sun goes down, so from the equator this isn’t going to be visible. If we very briefly go far into the Southern Hemisphere, even though the angle is comparable, there will be an angle, it will be reversed compared to what we see in the north. With the atmosphere turned off, Venus goes under the horizon well before the Sun and the inverse happens in the morning, the Sun comes up ahead of Venus. Saturn’s going to be nice and clearly visible from the Southern Hemisphere in the morning, but they’re not going to get Venus the way that we will here in Ireland. This is really a Northern Hemisphere phenomenon, because Venus is north of the Sun.

We’re going to keep seeing Venus above the horizon from the northern hemisphere at sunset and sunrise, as long as you’re horizon is clear, right through till about the 21st. You’ll certainly see it in the morning of the 21st, you’d need a very clear horizon see it in the evening of the 21st. Venus is going to look better and better in the morning over the coming weeks and Mercury and Saturn will join Venus then as well. Just for the next couple of days you’ve got the chance to see Venus twice, at sunset and sunrise.

I hope you get a chance to see Venus at least one of those times, even if you don’t get to see it at sunset and sunrise. I hope that you enjoyed this piece, if you did please do like it and if you enjoy this kind of content then you can subscribe to this website and my YouTube channel. Thank you for reading and hopefully I’ll see you back here next time.