Caoimhín's Content

We have just over a week to go until the eclipse, and don’t worry, at least the next post on this website will deal with the eclipse. Between 6 and 8 o’clock in Ireland, so 5 and 7 UTC, the sky will darken as the Moon moves in front of the Sun, making planets like Venus visible during the day. We’re going to look more at this from other locations besides Ireland next time, but before that, we’re going to take a look for the Perseid meteor shower and try to figure out where it’s going to look best.

We did this recently for the Southern Delta Aquariid meteor shower, and in order to see the Southern Delta Aquariid meteor shower well, we had to go into the south. We had to go into the Southern Hemisphere, changing our latitude as well as our longitude. As it turned out, we had to change our longitude quite a bit. In this case, we’re seeing the Perseids fairly close to the zenith just as the Sun comes up on the 13th and we’re seeing them very close to their peak of 100 meteors an hour. Of course, this is the peak predicted by Stellarium, there may be fewer meteors per hour in the real sky, these meteor showers do vary over time. The parent body of the Perseid meteor shower is the comet 109P/Swift-Tuttle. 109P means the 109th periodical comet discovered and it was discovered by Swift and Tuttle, these would be two second names. This comet is periodical, it goes around the Sun regularly, and when it passes by the Sun, as it moves through the solar system, it leaves behind a trail of material. When the Earth moves through that trail of material, some of it burns up in our atmosphere as meteors or shooting stars.

That’s really how most meteor showers work and that leads to some natural variability, depending on how long it’s been since we passed the stream and how long since the comet came through the stream. Furthermore, with long period comets that move past the orbits of planets like Jupiter, the gravity of Jupiter can have an influence on how much material is in the stream, how close that stream is to the Earth, and how many meteors we’re going to see. We’re not too far off great viewing conditions looking at the Perseids from here in Ireland. We need to move to a location where the Perseids are closer to the zenith while the sky is a little bit darker. So the first thing that we’re going to do is move a little bit to the east. That does bring the radiant a little bit higher in the sky, but we want them higher in the sky and closer to their peak of 100. We’ll come back to their peak of 100 and we’ll keep moving east because that does seem to be bringing the radiant higher in the sky. They do get higher in the sky as we move into Siberia, but we’re also getting a lot more influence from the sunrise. Moving down further South improves things, so we’re getting less influence from the sunrise, but we’re also seeing them a little off the zenith as well as we move below the Caspian Sea.

I’ve mentioned the zenith a lot, especially in relation to zenith hourly rates. If you look straight up into the middle of the sky, that is the zenith, where you would eb looking lying flat on your back. We want to get the Perseid meteor shower as close to that position in the sky as we can before the Sun comes up. The radiant will come up to the zenith in some locations further north, but after the Sun comes into the sky. We need to move lower on the planet, down to the Levant for example, which does allow things to get darker, but moves the Perseids away from the zenith. In between, around Romania and Ukraine, is a pretty good location. They are up at their max and at least the sky is dark. They’re not exactly on the zenith, but if we move higher on the planet to get them closer to the zenith, the Sun rises and the sky gets too bright. We have to move back in the direction of Ireland to get the sky dark again. Around Central Europe looks promising. Moving lower on the planet brings the radiant away from the zenith, moving higher on the planet brings the Sun back up. Somewhere around Germany, Poland, the Netherlands, by the looks of it, it could be one of the best positions to see the Perseids this year.

All of that was with the light pollution, which, of course makes our view worse. We will get rid of the light pollution to give ourselves the best possible view and the highest possible numbers, because that’s really what we’re aiming to do here. The maximum rate is projected to be 100, at the peak the current hourly rate is 100 and the current hourly rate, from around central Europe, is getting up towards the 90s as it approaches the zenith. Of course, it’s still not perfect. The radiant of the Perseid meteor shower is in the constellation of Perseus. Perseus isn’t on the ecliptic, so that means we’re not going to see the Perseids exactly on the zenith when we’re at the equator, and we’d have to move pretty far north to get the Perseids exactly on the zenith. We’re also seeing this in August when the constellation of Perseus is pretty close to the Sun. Not very close to the Sun, of course, there’s a bit of a gap, but we are seeing the peak close to 3 o’clock in the morning, we have to wait until close to sunrise before the radiant gets high in the sky. We’ll move around a little bit more now that we are in the countryside to see if we can make things a little bit better, to see if we can get more meteors.

The Perseids are a tricky meteor shower to see perfectly. Some meteor showers are visible at the zenith when the Sun is on the opposite side of the sky, at midnight. Some meteor showers for some locations peak when the meteor shower is actually at the zenith and it’s completely dark, but not all meteor showers do. Some meteor showers peak closer to sunrise, some meteor showers peak where, due to the seasons, they’re going to be close to the Sun no matter what happens. Sometimes their going to be very low in the sky from many locations. As we saw with the Southern Delta Aquariids, they don’t look great from Ireland because you need to be in the Southern Hemisphere to really get the best view. It looks like a good chunk of the world, if you’re in the countryside, will get a good view of this shower. A large portion of Europe, particularly eastern and Northern Europe, are going to get a great view of these meteor showers, and we can see even if we move to less ideal conditions, we’re still getting a pretty good view, up to 73 from southern Spain.

I will show what this looks like from over in the United States, around the middle of the United States, just to give you an idea. Here, the radiant of the Perseids is really low in the sky when it’s close to peaking, we’re looking at this in the countryside and we’re only getting a rate of seven. As it climbs higher in the sky, the amount of meteors locally climbs, but it’s only high in the sky when it’s far from the peak, so that drops the amount of meteors you can potentially see, even lower than what we can see here in Ireland when it’s at its peak. So the Perseid meteor shower, it’s really a particularly good one for us in Ireland, at least this year. Sometimes the peaks happen when the radiant is over a different location of the Earth. The amount of times the Earth rotates, with our 365 day year really really being a 365 and a quarter day year, things do move around a little bit relative to dates. In the United States the maximum is being given for the 12th, so I will change the date just in case, but of course, I believe that’s due to time zones more than anything else, the best local conditions are still after midnight on the 12th. If we move back, earlier on the 12th, we get closer to the actual peak of the meteor shower, but the amount of meteors visible to this location is lower, as we move forward, we come further from the peak of the meteor shower, but the amount of meteors visible for this location does go up. It looks like very close to morning time on the 13th will be the best time to see this in the United States, for the middle of the United States. Of course it’s a very big place, but generally in North America, you’re going to want to wait until morning time for the radiant to get high in the sky, much as we will here, but unfortunately not quite as close to the peak.

That is the Perseid meteor shower, I want to make a deal out of it because of course, on the 12th we’re going to have the solar eclipse. I think a lot of people will be looking at the sky, hopefully with the right protection. I think people are going to be looking at things to do with astronomy on this date anyway. I think it is worth waiting an extra couple of hours, enjoying the eclipse, seeing the eclipse happening and then after the eclipse, waiting until the sky gets dark, waiting until a little closer to morning time and seeing the Perseid meteor shower as it comes through the sky. We don’t even have to wait until close to morning time. Back in the city, just after physical midnight, and the rate is up to 29 meteors an hour. If you’re more of an early riser, that could work as well because we will be getting closer to the peak as we get closer to morning time. That brings us up to about 40 meteors an hour, even in the city, just before the sky gets too bright. Again, other meteor showers would contribute if any were peaking close enough to this date, but none of them really are. A lot of them are peaking earlier or later in August, but none of them are anywhere near as productive. None of them will contribute anywhere near as many meteors to the sky as the Perseids can.

The Perseids are one of the better meteor showers that we see during the year, so I don’t want people to forget about them just because there’s a solar eclipse on the same day. Of course, we get the Perseids every year and we don’t get a solar eclipse every year. If you are in Spain, you will get at least the chance to see some solar eclipse for the next three years and that’s something we will talk about in a future piece, so I hope you come back for that. I hope you enjoyed this piece. I hope you get to see the Perseids in the real sky. If you did enjoy this piece, 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 watching and hopefully I’ll see you back here next time.