Caoimhín's Content

Today we are going to take a trip to the Southern Hemisphere. As I was making the video associated with this article, I saw that the last time I gave a look at the Southern Hemisphere’s sky was this time of the year last year. Here in the Northern Hemisphere we are now leaving summertime, we’re in autumn and we’re heading into winter time. This of course means that down on the other side of the planet the very opposite is happening, and this may be the reason why this time of the year is when I tend to think of the Southern Hemisphere.

We will start with the sky from South America. On the 2nd of October there was an annular solar eclipse visible from the far South of South America, in Argentina and Chile. We will look at the sky from roughly where the eclipse was visible, but focusing on night time and beginning as usual with the start of the night. Looking at the sky to the south from the Southern hemisphere, the stars will move in the expected, circular fashion. Despite being expected, it’s always a little bit disorienting, looking South and seeing the stars appear to rotate in that way. I’m used to seeing that happening in the North, so seeing it when we are looking South, seems a bit odd. Looking to the north there are some familiar constellations, but everything’s upside down. For someone much more familiar with the constellations the other way around, I don’t know what’s what when I’m looking at the sky upside down like this. However, we can see that over the West Venus is nice and high in the sky and we’ve got Saturn even higher in the sky as well. Of course, the planets are nice and high to the North rather than nice and high to the South, but still the same planets in roughly the same location, especially when they are closer to the horizon, as Venus is. If we move forward in time towards morning, Jupiter and then mars will rise in the Northeast, continuing to rise until they are up over the North, along with the upside down Orion.

Turning back around to the South, and there are a bunch of constellations that I’m not familiar with. Among the most famous is the Southern Cross. The Southern Cross does look like a cross, even when you only have the stars to go off of. With the lines and then images of the constellations visible, the Cross will be even more obvious of course. As we move through time and the stars seem to rotate, the midpoint of that rotation will be directly over the South Pole. The Southern Cross roughly points at that midpoint in the sky, just like Plough or Big Dipper does from here in the North. Unfortunately, there isn’t really a Pole Star for the southern pole, the way we have the North Pole star here in the North.

If you are lucky enough to be down in the Southern Hemisphere, then there is a slightly better chance that you’ll be near a dark-sky than those of us that live in the Northern Hemisphere. Partly, this is due to the fact that there’s a lot more ocean in the Southern Hemisphere. Nobody builds buildings on the oceans, not yet at least. By looking at a dark sky in the Southern Hemisphere, we can see the lovely glow of the Milky Way, and we can also see the Large and Small Magellanic Clouds. This pair of dwarf galaxies, which may get renamed, are best seen from down in the South. In the North, there’s Orion’s Sword, appearing to point up into the sky, which looks a little strange, and the Pleiades are there, also appearing upside compared to what we’re used to in the Northern Hemisphere.

Watching the Sun set from a dark sky in the Southern Hemisphere is particularly nice at this time of the year. The core of the Milky Way should still be visible above the horizon to the West. Even from a location way down at the tip of Tierra del Fuego, at the bottom of Chile and Argentina, the bottom of the South American continent. This is almost as far South as you can get without going to Antarctica, but we’re still seeing a lot more of the central portion of the Milky Way here, compared to what we would be seeing in Ireland. We’re still a little further North than this South, and parts of the Northern Hemisphere are inhabited even further North again. The glow of the Milky Way is not directly behind the Sun yet, but it is still moving in that direction, or appears to be thanks to our motion. In the Southern Hemisphere this is happening while they are moving towards summer rather than moving towards winter. In the North, we don’t get to see the core of the Milky Way in winter, but in the Southern Hemisphere they don’t get to see the core of the Milky Way in summer. They will see the core of the Milky Way setting just after sunset, and closer to the equator even more of that core is visible, making it potentially even more impressive.

With that, we will move a little further North within the Southern hemisphere, to see the view from closer to the equator, but still South of it. I like showing the sky from way down in the South of of South America in particular, because it is so extreme, being about as far South as you can get on a continent. To move a little to the North, we will head to Australia, particularly to the Southern Coast, just where the coast begins to bend South towards Tasmania. This is around Adelaide, which has a nice bay that isn’t quite visible with the level of magnification that the location map in Stellarium provides. This is not as far South as Australia can get, we’re not at the southernmost point of Australia down on the island of Tasmania, but we are still firmly in the Southern Hemisphere. It’s just not quite as far South as Tierra del Fuego, nor as far South as we are North here in Ireland. We would certainly still see the lovely glow of the Milky Way, along with the Southern Cross and the Large and Small Magellanic Clouds. Towards the North, especially as the night progresses, it is all the outer arm of the Milky Way, that we can see. Looking at the sky in the morning, Mars will still be visible along with Jupiter, and Uranus in a very dark sky. The upside-down Pleiades along with Orion are a little bit higher in the sky, as are the planets. The same way that Southern Europe would see Orion higher in the sky than we do, Australia will see it higher than Southern South America, because they’re closer to the equator. Whether you’re in the Southern Hemisphere or the Northern Hemisphere, if you get a little bit closer to the equator you’ll see that little bit more of the constellations that are in and around the ecliptic.

Moving back into the early evening, two of the stars in the Summer Triangle, Altair and Vega, are visible to the North as well. It is easier an easier to see some familiar stars the further North we get, even remaining in the Southern Hemisphere. Just before sunset, the core of the Milky Way is almost directly above the West, letting us see all of the of lovely colours. We’re really seeing all of the middle of the Milky Way from here, even that bulge around the center, tailing away into the arms at either side. Some of the stars we’re seeing here are stars that we would see in Northern Hemisphere. It may be hard to spot even familiar shapes, from here they’re not quite upside down, but rather lying on their sides compared to what we’re used to seeing. With the images of the constellations up, which I have to do help myself spot them at all, we can see Sagittarius, almost above the core to the West, with that teapot shape. Extending down from the core towards the horizon we’ve got Scorpius the Scorpion, and all of the tail of Scorpius is up. Our horizon would pretty much cut across the core of the Milky Way here, blocking out most of the Scorpion, with the top Sagittarius still largely visible at sunset for another while. The Southern Coast of Australia is still pretty far South, but we can see the glow of the Milky Way is almost overhead even there. The equator is still further North, so we will push a little further northward. In South Africa or even Northern Australia, you would get to see a bit more of the ecliptic, it would be closer to overhead, not as low in the sky.

We will push much closer to the equator than that, all the way to northern Brazil. The northernmost part of Brazil is in fact North of the equator, so of course we won’t go that far, but quite close, up to around 7 degrees South. From here, again letting the Sun go down and looking into the West, we can still see all of the Milky Way’s core, but it is a little bit more tilted, not as close to being parallel to the horizon. This puts Scorpius and Sagittarius a little to the Southwest, and makes them closer to the orientation we’re used to seeing. We can still see the, one of the Magellanic clouds towards the South, whether they are both visible or not visible at all varies with the time of year, as with most things in the sky. Looking around to the North we’ve got the Summer Triangle, now that we’re in the Southern Hemisphere we’re seeing the Summer Triangle in the North, whereas we normally see it in the South, same with Delphinus and the other associated constellations. As we’re so much closer to the equator, Saturn practically looks like it’s over head. At Sun set Venus will appear and seem to drop straight down to wards the horizon. The lack of tilt in the ecliptic will allow Venus to appear much higher in the sky and much further from the Sun. Even though the Earth’s equator and the Sun’s equator don’t point in exactly the same direction, they’re pretty close, so our position on the Earth does make a big difference to how we see the planets. In the morning Mars and Jupiter will also seem really high in the sky as they rise ahead of the Sun.

We can see that the sky is changing for the Southern Hemisphere just as it is for us in many ways. The core of the Milky Way will be disappearing behind the Sun, just like it is for us, but because the Southern Hemisphere is in the Southern Hemisphere they’re going to be moving into summer when they lose the glow of the Milky Way. During winter for the Southern Hemisphere the glow of the Milky Way is closer to over head, which may be a slightly better deal than what we get here in the Northern Hemisphere. We of course don’t get to see the glow of the Milky Way during our long winter nights. From most parts of the Southern Hemisphere we can see some shared constellations, especially closer to the equator. Looking North from about 11 degrees South, you can see a lot of the constellations that we see in the Northern Hemisphere, even ones like Draco, Cepheus and Cassiopeia, that are rather close to the North Pole star. However, they would be quite low in the sky. From Northern Brazil you can even see Corona Borealis, because it’s still pretty close to the equator. The Northern Hemisphere is just around the corner if you’re only at a few degrees South.

The stars look a lot less familiar when you push further down into the Southern Hemisphere. We’ll make that huge jump again, all the way down 52 or 54 degrees South, as far South as Ireland is North. Leaving the Sun go down, and looking into the South, of course we’ll see all of those different constellations. If we turn around to the North, any shared constellations will really be skirting the horizon. We can just barely see the zodiacal constellations, with the planets and the ecliptic as low as they would be for our summer nights. As soon as we lean back even a little bit, it’s those Southern Hemisphere constellations that we wouldn’t see here in the North that cover the sky. We don’t get to see all Eridanus the River from Ireland, it disappears below our horizon, but in the South it curves it’s whole path across the sky. There are plenty of constellations that we don’t get to see at all, such as Horologium the Clock, those are things that are completely out of view for us. We’ll push backwards to sunset to get Saturn back into the sky, and from this far South it doesn’t seem that Corona Borealis is visible at all. As it is still really only Spring and because we’re looking at the sky closer to sunset, we’re seeing the ecliptic just that little bit higher going across the sky, and we can see a few more of the shared constellations. Still, from as far South as Ireland is North, the sky is dominated by those more unfamiliar pictures in the sky.

I hope you enjoyed this quick piece on the sky in the Southern Hemisphere. If you’re from the Southern Hemisphere then of course this is the sky you’re familiar with, but I still hope you enjoyed seeing it get talked about. In astronomy and many things the Northern Hemisphere hogs the spotlight, but it’s good to take a look down South every now and again as well. For whatever reason, if you did enjoy this piece then please do like it, and if you like this kind of content feel free to subscribe to this website and my YouTube channel. Hopefully, I’ll see you back here next time.