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Today, we are going to be taking a look at the night sky in October. We will be looking at the constellations, but we aren’t going to stick with just this month. Rather, we are going to see how the constellations will shift from this month into winter.

You may have seen my previous piece where we took a look at some of the constellations as they looked in the reasonably distant past, this time we’re going stick to the modern day. We’re starting in October, but a little bit closer to the middle of October, so that the sky is more significantly different from what we were seeing already in September. Looking just after sunset, just as the sky gets truly dark, Scorpius has already set but we’re still catching a little bit of Sagittarius. More and more coming into the sky are constellations like Pegasus, Andromeda and Perseus. We’re already seeing Taurus as the Sun sets. The stars unfortunately aren’t as visible in the city, so let’s push straight out to the countryside so that we can see a few more of the stars. In a darker sky, the Pleiades are visible, they’re already up as the Sun goes down, as the sky gets dark.

Looking at just 8 o’clock in the countryside, we still have a little bit of sunset glow over in the west, but the Pleiades are already up. If we move just a little bit later into what more people would call nighttime, we’ll see more. By 10 o’clock, 9 o’clock is even a little bit too early to really call it nighttime, Taurus is completely above the horizon and we’re starting to see parts of Gemini. We’ve mostly lost our indicators for the core of the Milky Way, but there’s a little bit of Sagittarius’s cape still sticking over the southern horizon, and we’re still seeing the upper part of Ophiuchus and part of Serpens, Serpens Cauda, the tail of the snake. Even this early, just a little after 10 o’clock, the Summer Triangle is very much in the south west, we’re already starting to lose it. We still have Corona Borealis up in due west, so if there’s going to be a supernova, it would still be a good time for it to happen. A potential nova in this constellation has been predicted to occur soon since this time last year.

Turning to the north, we’ve got the Plough right under the North Star by the time we’re through 10 o’clock. The positions of all of these constellations can help us to tell the time of night and the time of the year. We’re not going to have constellations like Taurus making an impression early in the evening until we are through to October. At other times of the night, we’ll see Taurus in different places. For example looking at the morning sky at 4:15, we’re able to see Taurus and Orion nice and high in the middle of the sky, due south. This is essentially a preview of what we’re going to see in the early evening, at 9 o’clock, in just a couple of months time, and that’s something that we can check. We can compare the 4:15 am sky in October with the 9 pm sky later in the year.

Let to the early evening, 10 o’clock, which is certainly nighttime once we’re through to late autumn. From here, we can move forward day by day, at the same time. Orion is already coming into the sky at that time by the end of next month. By the time we’re through to December we’re starting to get Orion and Taurus into the middle of the sky. Once we’re in January, the sky looks the exact same as 4:15 in October. We’ll ignore the planets for now, but these are the stars in the same positions. This sky that we can see now in October in the morning is the same sky that we’re going to see in January at closer to 9 o’clock. Daylight savings time has now been taken away, we’re no longer at UTC +1, so that’s going to make a difference in the time, but we can see it’s the exact same stuff in the exact same positions.

When you see the constellations and where the constellations are in the sky is a great indicator of the time of year and the time of the night, as long as you know one of them roughly. If you know roughly what time of year it is, then looking at the stars in the sky can give you an idea of what time of the night it is, if you know what time it is, then taking a look at the stars in the sky can give you a rough idea of of the time of year, particularly with the plough and the North Star. In october, early in the night, the Big Bear is right under the Little Bear, with Ursa Major pointing at Ursa Minor as always. At 10:30, we’ve got the Plough right under the North Star in October. Moving forward to that time of 4:15 (we might as well stick with similar times) and the Plough is just off to the side, off to the northeast. So if everything works the way we’d expect, then we would expect to see the same positions in January at about 9 o’clock.

We’ll pull back to 10 o’clock and we’ll allow the change of daylight savings to make it 9 o’clock as we come past the correct date in November. As we move from October, the positions of the stars seem to change. As we come back into January at 9 o’clock, the constellations end up in the positions that we’d expect. Even though these constellations both move over the course of the night and appear to change position over the course of the year as well, both of those processes are sort of balanced. Where we see the stars doesn’t really change, they stay in the same places. We can get a preview of months in advance just by changing what time of the night we go out. Of course, both the northern sky and with the southern sky, the sky in general, is going to be blocked by the Sun coming up. There are going to be stars that we cannot see in mid-to-late October that we will be able to see in the middle of summer, stars that that are behind the Sun. However, they’re never behind the Sun for very long.

There are certain constellations that will be blocked out at certain times of the year, but the will always come back into view. Looking forward to sunrise in October at 6:50 am, we’ve got Virgo and Leo in the sky, with Virgo just coming up out of the east. In several months, once we’re into February, we’re going to be able to see those constellations at a time closer to sunset. Again we’ll say 10 o’clock for here in summertime, and October is still in summertime according to daylight savings, but it will be 9 o’clock, once we’re through to November. We won’t have gone back into summertime by the time things line up, just into February. By about mid February we have Virgo and Leo up, with a Virgo just coming up over the eastern horizon,

They’re the same constellations and they’re in the same places relative to each other. Where they are isn’t changing, all that’s changing is the time of the night at which we see them, where they are at a given time and that’s down to the Earth moving around the Sun. As we change position around the Sun we’ll see the stars in different positions, and us moving in a circle around the Sun has a very similar effect to where we see things in the sky as the Earth turning in a circle over the course of a night and a day. Of course, it is on a slightly longer time scale. It only takes take 8 hours for Virgo and Leo to get back into those positions to appear by morning in October. To change their positions according to our motion along the Sun, to get them in the same positions 8 hours earlier, that’s going to take months. That’s going to take the rest of autumn and basically all of winter for us to accomplish, for us to move the right amount.

The changing positions of these things in the sky, they change because of our rotation and our orbit around the Sun. They don’t change relative to each other especially over reasonably short timescales and even looking back to the negative 1800s, as we did in the last piece, you could still recognize the shapes of these constellations, you could still recognize Orion and Taurus because the stars are still in the same relative positions. The stars do move, but on a human timescale, they might as well be fixed and that makes them very reliable for telling the time, telling the time of year and telling when things are. For example, the Summer Triangle, of course, that’s a particularly famous one, and named for its relation to northern summer. Even the Pleiades, if we come back to just as the Sun is setting in October, the Pleiades coming visible over there in the east was also an important marker of time for various cultures and various civilizations. When that little knot of stars gets into the sky, even though it’s so much smaller than the Summer Triangle, it’s still a very recognizable thing in the sky and easy to notice. Once you have this recognizable thing, you know when it’s going to pop up in the east, you know when it’ll be visible at sunset and you can even tell when it’s coming because it’ll get visible in the morning. From the moment that the Pleiades come out from behind the Sun, it sort of starts the clock until you see them coming up just as the Sun is setting.

That is a quick look at the modern constellations and how they change over the course of time, not really just a look at the constellations over the course of October, but of course we already saw them in September, and they do change slowly. Still, these are the constellations that we have in our sky and of course they change over time.

If you’d like to stay up to date with the changing of the constellations, make sure you subscribe to this website and my YouTube channel, because I do this at least once a month, taking a look at where things are going to be in the sky, and of course, we talk about plenty of other astronomical phenomenon as well. If you enjoyed this piece in particular, please do like it. If you like this kind of content, then do subscribe to this website. Thank you very much for watching and hopefully I’ll see you back here next time.