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Today we will be talking about navigation and stargazing, using the stars to find out where you are and what direction you are facing. We’re looking at the sky for the end of April this year, and the Moon will be full on the first day of May, Lá Fhéile Bealtaine. For that reason the Moon will be up for the majority of the night for this part of April, and close enough to full as well.

When we’re talking about navigation and the stars, the first thing that everybody thinks about is Réalt an Eolais, the North Star. We’re able to see it in the direction of north year round. If you are going northward, that star is going to go up and up until it is directly overhead. If you are going away from the North Star, it will sink down the sky until it hits the horizon when you hit the equator. The North Star is very very useful to find out what direction north is, and how close to north you are. If you measure the angle between that star and the ground, you’ll find out, almost anyway, how far north you are. Measuring in Stellarium, I got 51 degrees for Cork City, and really we’re 52 degrees north, that’s how close to the North Pole that we are. However, that star isn’t the only star that’s useful to find out where you are going, what direction you are going and also the times of the year. If you are trying to find the North Star, at this time of the year, at the start of the night, if you look almost straight up into the sky, you’ll find the Plough. If you go straight down from end of the Pot, away from the handle, if you go straight down that line you’ll get the North Star.

If you are navigating really, you won’t be in a city, there’s a lower chance that you’ll be in a city anyway. There’s a better chance that you’ll be out in the countryside, if you are trying to use the stars to find out where you are seriously, rather than doing it as practice or as a hobby. If you are in a city, there’s streets, there’s roads, usually it’s easier to find out where you are. Still you’re able to use the Plough in the city and find the North Star. The North Star isn’t very very bright, but it is brighter than the stars that are directly next to it. Also on the other side is the sort of W-shape of Cassiopeia. If you watch out for that shape, you’ll know if you went to far from the Plough. You have to stop about five times the length of the end of the Plough for the North Star. There are other things that are useful, but hey change with the time of year. If you are watching out for what stars are rising, for example if you are trying to find the east, if you know that we’re almost at summer, the Summer Triangle will be in the direction of east.

That works the start of summer, if we are at the start of summer, and we will be at the start of summer in a week or two once we’re into May. If you are at the start of summer or coming up to summer, the summer triangle will be in the east at the start of the night, in late April it’s fully up by 1 o’clock. However when you go further forward, months and months ahead to the end of summer, then the Summer triangle will be on the opposite side of the sky when the Sun is setting. You need to be careful regarding the time of the year if you are using things that aren’t the North Star, or the Southern Cross. If you are using the Cross, if you are down on the other side of the Earth, that works for every time of the year as well. However, for things like the summer triangle, or the Pleiades, the time of year matters. The Pleiades aren’t up much at the moment but they will be up again in the future. The Seven Sisters, the Pleiades, whatever name you prefer to give them, they are over in the west just after sunset, very low in the sky.. The Seven Sisters are setting in the direction of west at this time of the year, but at other times of the year they’ll be coming up in the east. Therefore, you need to know the time of year if you are using the other stars to find out the direction. However, if you are comfortable with the time of year, if you know that the Summer triangle is in the east at the start of the night at the start of summer, and in the west at the start of the night at the end of summer, if you know that then you’ll be able to use it at those times of the year.

When people were out using the stars for navigation, stellar navigation without astronomy, when people were doing that genuinely, natively, people were out in the countryside for much longer lengths of time. People were out with the stars, looking at the sky and getting comfortable with what is happening at different times of the year, and for that reason they had experience. They had experience with where the stars were and where they go. They were able to use, for example, the place of the Plough in the sky to measure how long they were outside, how long they were looking at the stars and that changes with the time of year as well. Into May, the Plough is right up, almost in the middle of the sky, right at the start of the night. If we pull back to April, even around now, even at the end of April, when the Sun is setting, the Plough is further to the side, further in the direction of east.

You can still look at how far the Plough is after circling, how far it’s after moving, and use that to find out how long you’ve been outside, how long you were looking at the stars. However, what place the Plough will be in, that depends on the time of the year. To look at the whole year, it’s best we look at midnight. We need to be at 1:30 for our midnight, our real physical midnight, rather than midnight on the clock. At the moment we have UTC and an extra hour due to summer time. Looking at the sky at night, we can see if we go through the year, still looking at the same time, the Plough changes position. The time on the clock will change due to summer time going back to winter time, but that’s our problem. That’s a problem created by people rather than the stars. Either way, the Plough circles the North Star if you go out at the same time each and every night. The Plough circles the North Star over the course of the year, and within one night the Plough circles the North Star as well. Once you have experience with the stars you don’t have to look around, you don’t have to think “Is the Plough above or below the North Star. You’ll know, “Oh, the weather’s nice, we’re into May or the end of April, the Plough will be high in the sky”, or, “Oh, it’s winter, the weather’s cold, the Plough will be low in the sky at the start of the night”.

You have to gain experience to do use those things for navigation, but on the other hand, it’s very easy to use the North Star for navigation. The job of stellar navigation was a lot harder and a lot more important long ago. It’s a lot easier today with the technology that we have to find out where you are, and it would be a lot harder to use the stars to find out where you are due to the light pollution. We can’t see as many stars, and it isn’t as easy to gain experience with the stars. Even the view I use in Stellarium, although the light pollution is like the light pollution of the city, the view is still a lot better than cities usually are. There’s no background of a city in Stellarium, but there is one with many tall tree. That view is still nicer, more comfortable maybe, but if there are trees around you a lot of the sky will be missing, you won’t be able to see things because there’s trees in the way. It’s the same thing in the city, there’s too many buildings and those buildings are able to cover your view, you won’t be able to see the stars due to the buildings in the way. Even if you were in a totally dark sky, there’s less of the sky to see.

That’s another problem and maybe a problem to talk more about in another piece, but that’s a little about the stars, navigation and how to use them, mostly for the main one for the, for the North Star, and some of the problems with doing it today. If you enjoyed this piece then make sure you like it, if you enjoy this topic then make sure you subscribe to this website and my YouTube channel. Thank you very much for reading and hopefully I’ll see you back here next time.