Caoimhín's Content

Today we are going to be taking a look at the constellations that we’re going to see over the course of the month of April. Taking a look at the sky for mid-April and looking at the daytime sky, the Sun is almost directly in the south at just about 1:30, because we are at UTC+1 in Ireland. We are definitely using the summertime part of daylight savings time. The height of the Sun above the horizon at this midday peak is getting higher and higher. It will continue to get higher, of course, but it was much lower even just a month ago, it was significantly lower in the sky. We are certainly coming back into summertime and that means our constellations are going to look more summery. They are going to look more like the constellations that we see in the summer, especially later in the night.

By mid-April the Sun is setting at just about 8 o’clock and the sky won’t really get dark until coming up to 9 o’clock. We do already have to wait until reasonably late before the sky gets dark enough to see things, but we’re not waiting as late as we will be when we truly enter summertime. We will possibly still be just on the edge of astronomical twilight at almost 10 o’clock. Taking a look over towards the east/northeast, only one side of the summer triangle is visible low on the sky, so according to the Summer Triangle we are still not in summer. Taking a look at the sky as we’d see it here in the city, we are still early in the night, still just about catching Orion and Taurus. Orion and Taurus in particular won’t be in the sky for long as they are already low to the west. Leo and Virgo are going to come to dominate the night sky over the next couple of months, they will be some of the main constellations appearing once the sky gets dark.

Bringing up our normal constellations, they are still the same. We’re still getting the same drawings. Stellarium did recently have an update and one of the main features of that update was an expanded degree of sky cultures and more different mythologies, but it seems the default has stayed the same. Now, rather than a list of cultures next to a description window, each sky culture gets its own window for description and setting what is visible once you have it selected. The exploration and selection of cultures is left over to separate tab. This other tab has the list of cultures and what looks like a hydrological map of the world. The different mythologies are now broken up in a different way, grouped by location. Along with the default constellations, there is a seperate modern IAU option, which doesn’t seem to provide any pictures. Normally, most of these would provide images, but there are plenty of other sky cultures to check out.

Some of them are being provided with images, but not all. Not all of the sky cultures would be provided with images, and many of them only have images in certain parts of the sky. Part of the reason for this is that some of these constellations and constellation groups are reconstructed. Some of them have been reconstructed quite thoroughly, for example the Babylonian constellations. Even then we can still see significant gaps in the sky, areas where constellations have not been filled in. There are also several constellations that we might recognize, such as the Bull and the Crab. There is a lot of variation, but the Babylonian constellations are related to the Arabic constellations and the Greek constellations, ando so our modern constellations as well. Of course, all of these things cultures happened reasonably close together in a fairly similar part of the world. Other constellations stem from different mythologies. It seems that some of the sky cultures use similar images to the default modern ones, although they would have been different.

One very well drawn depiction belongs is of the Chinese constellations, but there are still several similarities. For example a Bull, Twins, a Crab and a Lion, all in the same locations as their western counterparts. This depiction is no doubt influenced by the Western ones, there seems to be a little bit of a mix. Some of the constellations certainly seem different, or at least differently interpreted. However, it also includes newer constellations, such as Coma Berenice. These are newer constellations that have presumably been included now in modern Chinese astronomy, even though they would have been quite different originally. Even when there are no images for a culture, we’re getting the traditional names of some different stars. The Inuit constellations are another culture where only a few constellations are brought up, scattered across the sky. Although there is a very big variation in the sky cultures that are being provided, not all of them could be described as full, not covering the entire sky. Some of them are pretty full, such as a Greek one derived from the Almagest, from Ptolemy’s astronomy. There are a lot of very familiar constellations, for example Triangulum. It looks like Taurus and the Pleiades have been separated out, which is one way they were displayed in the past. These changes are things that were done in other mythologies. Different cultural groups painted different pictures in the sky.

It seems like the little map is able to indicate to us, at least in some occasions, where these images came from, where the culture was located. It does so for the Norse Edda constellations. The Edda is an epic story and a series of poems recording Norse mythology. Even here, some constellations seem related to our modern ones. It’s interesting that there is a bull or bulls head near Gemini. This area seems to be a bull’s head in a couple of different mythologies, even though our Taurus would be over with Aldebaran on the other side of Orion. It’s an interesting difference, even though a bull is used in multiple different mythologies, they do seem to be different bulls and in different locations in the sky.

Returning to our modern constellations that we normally see, Virgo is completely above the horizon. Turning around to the east is the Summer Triangle. The Summer Triangle still hasn’t risen fully into the sky. This is still only just about 10 o’clock, so we can move significantly later and this get a preview of the sort of view of the sky that we’re going to get in a month or so, by about June. The Summer Triangle is almost above the horizon by midnight. Also visible are Ophiuchus and Hercules coming up into the sky. The Plough, or Big Dipper, is almost at the zenith at midnight. However, this is our temporal midnight, midnight on the clock. We’re going to have to move a little further forward to account for UTC and our position on the Earth to reach physical local midnight. Moving forward to 1:30 does that, and moves the Plough a little further to the west. Also, the entire Summer Triangle is above the horizon. It does look like Altair down low is being occulted by the atmosphere, but it is above the horizon nonetheless. This is showing how close to summertime we’re getting, these constellations are different enough from our wintertime constellations, the ones that we’ve been enjoying for several months now. Pegasus is also starting to come back up in the morning.

By morning, the Summer Triangle is nice and high in the sky. Both Scorpius and Sagittarius are above the horizon. We’re just about starting to see a little bit of light as we get to 5 o’clock, which is about the time that we would transition into astronomical twilight. It is enough light to affect our view of the sky, but it’s not enough light to see what you’re doing for example. We’re going to move another day or two forward just to get the Moon out of the sky while the sky is still dark in the morning. At just 4:55, this should give us a good view of the Milky Way from the countryside. Once we’re rid of the light pollution we have the Milky Way stretching across the sky just as we’d expect. We do still have to wait until quite early in the morning to see a good view of the Milky Way, but not as early as a month ago. Even at 3:20 in the morning, we’ve got a reasonable amount of the core and the outer arm of the Milky Way there passing through the Summer Triangle is nice and clear.

The sky has only changed subtly since March. It is going to be another month before we really get into the summertime sky and the summertime constellations, but already we’re seeing a big difference in what constellations are prominent. Even though Orion is still visible and Aldebaran is still visible, they’re way over in the west, they’re quite low in the sky and they won’t be up for very long. By the time the sky gets dark Leo’s already high in the sky. We can already follow the curve of the handle of the Plough, the arc to Arcturus and spike on to Spica. We can do that really as soon as the sky is dark, which is something we would have to wait a few hours for even a month ago in March. So we’ve got some changes coming up to the sky. We’ve got some changes coming up to what’s going to be visible and there has been some changes with how Stellarium outlines its sky cultures. That’s something that we will no doubt explore further in a future video. It is interesting that some of these different sky cultures change the map, showing us where those cultures should be, but they don’t seem all to do that. We can’t click on the map and select that areas culture.

Hopefully I will be back exploring that feature in the near future but until then, I hope that you enjoyed this piece taking a look at the constellations in the sky for April. If you did enjoy it, then 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.