Caoimhín's Content

Today, we are going to be taking a look at the coming month of August.

We will start on the first day of August, Lá Fhéile Lughnasadh, as it’s known in Ireland. Lughnasadh is the month of August and the first day is the Festival of August. We’re finally getting out of summertime, so the sky is going to be reasonably dark at a much more reasonable time. By just 11 o’clock, the sky is pretty much entirely dark already and this is just the 1st of August. On the 1st, the Moon is still a reasonably narrow crescent, so it won’t be up for too much in the very early part of August, the first week or so. As we move a little bit later into the month, by the second week of August the Moon is pretty much full. We’re seeing the Moon at 99.7% full on the 8th. The Moon is going to be pretty close to full just before mid-August. Luckily, if we move forward to the 12th and 13th, the Moon barely in the sky when the Sun goes down. Once we’re through to the 12th and 13th of August, we can see that it is starting to get a little bit darker a little bit earlier. We should start getting darkness at just 10:30 instead of 11 o’clock.

We will very quickly bring up the meteor showers because of the Perseids. As the Sun sets the radiant will be up in the north east, radiating from the constellation Perseus, just next to Cassiopeia. The Perseids are peaking on the 12th. Whether we’re seeing them peak in the morning of the 12th or later in the evening of the 12th, whether or not we should stay up until just before midnight on the 12th or after midnight on the 11th, does vary from year to year and location to location. We can see they’re peaking there on the 12th of August with a zenith hourly rate of up to 100. Just after sunset, we’re seeing a zenith hourly rate of 97 from Ireland and a local hourly rate of 21 or so from Cork City. This is partly because of the light pollution and partly because of the Moon. If we go through a couple of days, the zenith hourly rate, or ZHR, definitely goes down on either side of the 12th, so we need to go observing the day of the 12th moving into the 13th. It look like the Perseids will peak just before the Sun sets here in Ireland, but well after the sunrise on the 12th. We can follow them through to morning time, but as we do the ZHR continues to drop.

We will talk more about the Perseids a little bit more once we’re slightly further into August. Once we’re through to sunrise on the th 12th, we can see Jupiter and Venus being very close together. It is quite a close conjunction that we have to look forward to on the morning of the 12th. We won’t chase them around the world to see where the conjunction is at its absolute best. They are reasonably separated so the chances of this being an occultation anywhere are pretty low. By moving through a couple of days, we can check that it is definitely on the 12th is when they’re at their closest.

Taking a closer look, we can already see some moons of Jupiter with Venus still in view. Of course, that would take a very wide field of view, it would be difficult to achieve with most telescopes. It’s nice to see that from here in Ireland, all four of the Galilean moons should be visible arranged around Jupiter. Occasionally some of Jupiter’s moons can pile up with each other or disappear behind the planet, meaning only two or three of the four will be visible. It looks like the 11th might actually be better a better day to see the four moons all separated out, at least from Ireland. Io is a little bit further out from Jupiter on the 11th, which is going to make it easier to see on its own through a telescope. Coming back here to the 12th, Io and Europa are much closer to Jupiter. You can see them moving around if you’re willing to go out over the course of a couple of days. Also, the moons of Jupiter move quickly, meaning they could be in different positions by the time the Sun rises for the Pacific after we see them at sunrise here in Ireland. Taking a closer look at Venus, of course all we’re going to see is the thick atmosphere, but it does look pretty close to a half Venus. Venus is not quite at its greatest elongation, we’d have to come back all the way to July to see Venus at its greatest elongation, but it still far from the Sun and prominent in August. As we move through the month, Venus is moving away from its greatest elongation, it’s going away from the Earth and out behind the Sun, but we’re still seeing part of it in shadow on the 12th which will make it that little bit more interesting through a telescope.

You might start catching a brief view of Mercury at sunrise by mid-August, but if we move later, we can see Mercury coming up a little bit better later in the month. By the 20th we can see Mercury, Venus, Jupiter, the Moon, and the two twins of Gemini here, Pollux and Castor, all just above the sunrise. We’re also getting a reasonable view of Orion once we’re through to the end of the month. Even on the 20th, by 5 o’clock the sky still isn’t too bright. Also still up at 5 o’clock in the morning is Saturn over to the southwest. Of course, Uranus is out by the Pleiades and Neptune is out by Saturn as well, so we’re only missing Mars. We’re seeing almost every planet that’s visible to the naked eye, plus the two planets in our solar system that are not visible to the naked eye, all there in the morning sky. Mercury should still be visible at 5 o’clock from the city. As we get later, we’ll still have the Moon, Venus and Jupiter, but just the three of them are left by a little after 6 o’clock.

Once we’re through to the end of August, we’re really going to start seeing the days feeling shorter, even though the days will continue to be longer than the nights until we get through till September. We’re going to start noticing that the sunset is a little bit earlier and it will be truly dark by midnight. A little before 10:30, the sky is dark at the end of the month. There’s a little bit of sunlight coming up over the north at that time, but as we move through to midnight it is completely dark, there’s no glow of the Sun really coming over the north. We’ve left that portion of summertime once we’re past the first day of August, once we’re past Lughnasadh.

That was all looking at the sky as we would see it from here in the city, so we’ll head out to the countryside to hopefully get a slightly better view. Once we are out in the countryside, we’ve got that glow of the Milky Way. However, if we come back a little bit closer to the middle of August, firstly the glow of the Moon will block out portions of the Milky Way. We’re still seeing the summer triangle here as the Sun goes down, in early August, we might still see it until the Sun comes up in the morning, but we’re definitely leaving summer once we come into August, so the summer triangle should be leaving the sky. It can at least show you where to look early in the evening. As the sky darkens, we can see the Milky Way coming up at about 11 o’clock, but we’re already losing Antares at that time, so the core of the Milky Way is still going to set reasonably early. We do have the arms of the Milky Way stretching across the sky, but they are much fainter. If we move later in the month, that will get the Moon out of the way, but you can see that if we’re going out at the same time, once we’re through till here on the 30th of August, the core of the Milky Way is already starting to set, and if we come just a little bit earlier, we’ll start to get that brightness back in the sky. The Milky Way should still be visible at a closer to 10 o’clock in the countryside, but with the Moon and the light of the Sun, we’ll have to wait until after 9:30, closer to 10 o’clock, before it comes out.

Saturn’s nice and clear and visible essentially for the entire night. That’s going to make it even easier to point a telescope at it, it’s going to be there for the entire night, so you’ll have plenty of time to line up your telescope to take a look. Of course, it’s important to remember that you’ll have to adjust the position of your telescope over the course of the night in order to keep following Saturn across the sky. By the very end of the month, even though Venus and Jupiter were quite close together on the 12th in a reasonably close conjunction, we can see there’s quite a bit of distance here by the time we’re through to the 31st. That’s partly due to how fast Venus moves around the Sun. We can see Mercury there pretty well, but Mercury is heading back towards the Sun. It looks like the 18th is when Mercury will be at its closest to Venus, roughly at its greatest elongation, before it starts moving away. Venus will be following it, of course, Venus is also going behind the Sun, so they’re both moving in a similar way.

We can see here in the morning how much brighter it is earlier in the month at nearly 6 o’clock, whereas at the end of the month at about 6 o’clock, the sky is, from the countryside at least, still dark enough to see some of the really prominent and famous things that are going to become more obvious once we get into winter. We’ve got Sirius the brightest star just above the horizon. We’ve got Orion above that and we’ve got the Hyades and the Pleiades a little higher again. We’ve got all of these things that are going to be more prominent in the early evening once we get into winter, but we’re starting to see them at sunrise, and of course all of those planets together as well.

I do want to say thank you for a commenter who suggested looking at a few of these dates, the 20th for this nice conjunction of Venus, Jupiter, the Moon, Pollux, with Mercury a little lower in the sky and Saturn up as well. Also coming back to the 12th, to see Jupiter and Venus there at their close conjunction. That commenter did also suggest looking at the Perseids, and we will look at the Perseids, I will dedicate a piece to the Perseids, once we get a little bit later into the month, once it’s closer to them happening.

I do hope that you enjoyed this piece, if you did, please do like it. Also, if you have anything that you’d like to see in the sky, any suggestions for any events coming up, even if they’re hundreds of years in the future, do let me know. I always like showing things that people want to see, and if you tell me that you want to see something, then I know for sure that it’s worth making a piece about it. If you enjoyed this video and if you enjoy this kind of content, then please subscribe to this YouTube channel. Thank you very much for watching and hopefully I’ll see you back here next time.