Caoimhín's Content

Today we are going to take a look at a couple of conjunctions that we’re not going to see in January. Some things are only visible from certain locations on Earth, for example, any solar eclipse will only be visible for a reasonably narrow portion of the Earth. This is true for many conjunctions as well, or occultations, they often are only visible to certain very specific locations. These conjunctions however, are ones that we don’t get to see at all.

You may have noticed the lack of Mars in the past few reviews of the night sky. We haven’t really had a good view of Mars, certainly not here in Ireland, for a couple of months now, and it’s not going to come back until it’s finished going behind the Sun. You may have also noticed, and I have mentioned it recently, Venus going out of the morning sky. We had a morning time view of Venus back in even early December, but by late December and certainly coming into January, Venus is getting behind of the Sun. This is particularly true on the 6th for Venus’s conjunction with the Sun. This gives us a full Venus on the far side of the Sun, fully illuminated. This is a superior conjunction, we do have inferior conjunctions as well when planets come in front of the Sun. That can only happen with planets like Venus and Mercury that are closer to the Sun. For planets like Mars, they have opposition when they’re directly behind us, just like Jupiter on the 10th, but on the 9th we have Mars’s superior conjunction, when it’s directly in line with the Sun and therefore invisible from the Earth. This also shows us Mars fully illuminated, currently with a nice view of its south pole. Mars is directly behind the Sun on the 9th, invisible to us, Venus is directly behind the Sun on the 6th, also invisible to us, and around the 7th and the 8th, the two planets are quite close together in the sky, both equally invisible to us.

Just earlier this year we had a phenomenon of Venus visible in the morning and in the evening, at sunset and sunrise, because Venus appeared to be above the Sun from our perspective. Venus isn’t quite far enough below the Sun for that to be achievable in the southern hemisphere this time. I don’t think Venus or Mars are going to be visible to the southern hemisphere as the Sun as going down when they are at conjunction, they’re not quite far enough away from the Sun in the sky. This kind of conjunction is an interesting counterpart to events like the opposition of Jupiter and the conjunctions that we would normally see in the sky when things come close together. For example, the conjunction that we’re getting in early January between the Moon, Jupiter and Pollux. Jupiter is close to opposition, so that means it has to be rising about the time the Sun is setting. It’s a bit below Pollux all month. On the 4th, we get the conjunction of Jupiter, the Moon and Pollux, all visible pretty much in a straight line. Jupiter really is behind the Moon, Pollux is then even further behind Jupiter, but they’re not in a straight line. This means we can still see all of them, so it’s not the same as an occultation. Lining up perfectly can happen with the superior conjunction of planets and the Sun. Occasionally when a planet is at superior conjunction, it will be directly behind the Sun and completely blocked from our view.

That’s not the case for the two this month. In order to catch one of those, we’re going to have to go back through time to get one of the planets in position. Moving back to last year, Jupiter disappears behind the Sun. This is on the 24th of the 6th, 2025, Jupiter was directly behind the Sun, not visible at all. This is roughly six months before the opposition because Jupiter’s motion around the Sun is so slow, where we see Jupiter in the sky relative to the Sun really depends on our motion around the Sun. There’s roughly one of our years between every Jupiter opposition, so there is about half a year between the superior conjunction with the Sun and Jupiter’s opposition, it’s half of the distance. For this superior conjunction, Jupiter was completely, perfectly, behind the Sun. We’ll come all the way back around to the superior conjunctions this month, which are technically a little bit more visible. With Venus and Mars back into view, somewhere around the 7th or 8th would be the best opportunity to potentially see the planets in the southern hemisphere. We were able to do see Venus at sunset and sunrise because it was north of the Sun, invisible to those in the Southern hemisphere. This time, the planets are south of the Sun.

If these planets are to be visible above the horizon at sunset, it’s only going to be visible in the southern hemisphere. We’ll start in the middle of the day, down in the southern hemisphere but also much closer to the equator. To give ourselves the best possible opportunity, we’ll go with a completely flat horizon so that there’s nothing at all in the way. With no atmosphere to interfere, Venus and Mars, they are technically above the horizon while the Sun is below the horizon, but barely. With the atmosphere, there will be too much of a glow, but also it causes a “jump”, which I’ve mentioned a few times before on this website. The atmosphere will bend light, so the Sun may be below the horizon, but the refraction of the atmosphere makes it appear as though the Sun is still above the horizon. Even with the Sun completely below the horizon, nothing’s quite bright enough, neither Mars nor Venus are quite bright enough, to shine out against the glow of the Sun.

We’ll hop into the countryside just in case it makes a sufficient difference. It just about brings Venus into view. It looks like people in the southern hemisphere, if in a very lucky position, might catch Venus at sunset on the 7th. Really it should be the 6th for the conjunction, but that does bring it a bit closer to the Sun.We’ll very quickly take a look at sunrise all the way over to the opposite horizon. With the different hemisphere, things curve to the opposite side, so the Sun will pas across the northern sky. If we get rid of the atmosphere, it doesn’t look like we will get Venus above the horizon at the right time by the right amount, not at least on the correct night. On the 4th it’s still just about visible in the morning. With the atmosphere on, it’s just barely visible, along with the comet 2024 E1, the comet that I mentioned in the previous piece. Venus is visible at sunrise on the 4th, so we need to come back around to sunset to check if it’s visible then.

With the Sun just on the horizon, unfortunately there’s no sign of Venus. WIth no atmosphere we can see Mars. Venus is just too close to the Sun this time, going down just at the wrong angle. However it looks like around these nights in the Southern hemisphere you’ll be able to see very close to Venus’s superior conjunction when it’s on the opposite side of the Sun. You should be able to see it approaching this superior conjunction by catching it in one side of the Sun as it rises and then on the opposite side of the Sun as the Sun sets, within a few days of each other. Here in Ireland, both of these planets are going to appear as though they are under the Sun in the sky when they reach these particular conjunctions. When there are perfect superior conjunctions, they really are conjunctions that we never see. This one is a little imperfect, but definitely not visible to those of us here in Ireland.

I hope that if you’re in the Southern hemisphere, you get to see Venus close to this conjunction, but no matter what hope I give, these kinds of conjunctions are usually invisible to us here on Earth. I hope you at least enjoyed reading this piece about them. If you did enjoy this piece, please do like it. If you like this kind of content, then please subscribe to this website and my YouTube channel. Thank you very much for reading and hopefully I’ll see you back here next time.