Caoimhín's Content

As usual, now that we’re coming to the end of the month, we’re going to take a look ahead to the next one. September is going to be a jam packed month, so this overview will skip over some of the details, but I will return to them as they occur. We will begin as we normally, by looking through the night early in the month, as we would see it from a city like Cork. Now that we’re really getting into autumn time, the Sun will be going down by just 8:30. We will still have some sunset glow at this time, but there will still be stars visible as nights are finally starting to begin reasonably early. The summer triangle will nice and high above the South as soon as it appears, and Saturn will already above the horizon once the sky darkens as well. Saturn will look better once it’s a little bit higher in the sky, it will still be quite low when it first appears and that means looking through a lot of atmosphere to see it. As we move towards midnight, even just coming up to 11 o’clock, the summer triangle will already be after moving pretty far to the West. Even this early in the night, Jupiter and Mars will be after rising over towards the Northeast. Just a couple of minutes after midnight both of those planets will be visible, but Mars in particular will still be pretty low in the sky. Jupiter should be at a reasonable height to observe just a little after midnight, and of course, both of those planets will continue getting higher and higher in the sky as we push closer to morning time.

Even though Mars and Jupiter will start to appear earlier in the evening, they are still going to be at their best in the morning. Pushing ahead towards sunrise will bring Mercury into the sky. Mercury is of course the closest planet to the Sun, so even at its best it will appear quite close to the sunrise in the morning. Mercury will be reaching its greatest western elongation early in the month of September, so it is going to start to be easier to see, as it will be at the furthest apparent distance form the Sun that it can get. From the city, that gives us four planets in the sky together, Mercury, Mars, Jupiter and Saturn. From the city that’s definitely all you’ll see, but Uranus is up at the moment as well. If you’re in the countryside with particularly good eyesight or if you have a telescope or a binoculars, Uranus should be near the Pleiades, quite close to Jupiter. Neptune is also in the sky, just over by Saturn so we do have almost every planet in the sky. Neptune is certainly invisible with out some assistance, but it will be above the horizon. We don’t quite have every planet, as we don’t have Venus, but 6 out of 7 isn’t too bad., We should have a particularly nice view, as the Moon won’t be in the way for the majority of the month, it will only come around to the morning sky close to the end of September. On the 1st of September, as the Sun is rising the Moon will be right on the horizon just ahead of it, at about 5 o’clock in the morning. If keep pushing ahead, things will start to disappear and once we come past 5 o’clock, Saturn and Mercury will be very faint. Mars and Jupiter will remain just about visible for longer. Jupiter of course is one of the brightest thing in the sky, brighter than any of the stars. Without Venus to compete with, Jupiter will be the last thing to disappear. The Moon will only be a very narrow, narrow crescent, it will very close to new, making incredibly difficult to see for the beginning of the month.

As we move into September the nights are going to start getting longer and longer. Mercury’s greatest elongation is on the 5th, but even through to the 10th of September, Mercury should be in the sky while it’s still reasonably dark. Mars and Jupiter will remain in the morning sky all month, but Saturn will not. Saturn is going to be passing its point of opposition later in the month. While it’s at opposition, it will be with us for the entire night, but once it’s passed opposition we’re mostly going to see it earlier in the night and in the evening, it will disappear in the morning. Saturn leaving the morning sky for the evening sky and Mercury moving back in towards the Sun will quickly bring us from 4 morning planets back to just 2.

Pushing through to the 17th, just after the middle of the month, will bring us to the night of the Full Moon. You may remember from a recent video that this Full Moon will be a Supermoon. Early on the night of the 17th it will only be 99.9% full, but if we move past midnight into the 18th it will come up to 100% full. Coming up to midnight, both Saturn and Moon will be close to their highest in the South, with the Moon being full and Saturn so close to opposition, and as they pass the South the Moon will reach 100%. This Full Moon will also be quite close to us, which is really what makes it a Supermoon. You can refer to on of my previous pieces about the not-quite-Super Blue Moon that we had in August if you’d like more details on Supermoons and the Moons varying distance from the Earth. Pushing forward just a little bit later in enough in the month and we will lose Saturn before the Sun actually rises. This gives us a reasonably narrow window, just the first couple of weeks of the month where we will have all those planets together in the sky. Once we get through to the end of the month Mercury will start moving out of view again and Saturn won’t be visible in the morning,

Continuing to push later into the month, on the 22nd we come up to the night of the equinox. In the morning, Saturn will be gone, Mercury will be gone, we will only have Mars, Jupiter, Uranus and the Moon, in the sky. Not only will those objects still be up, but we can also see Orion nice and high in the sky early in the morning as we come to the end of the month. By the end of September the Moon will have passed through the morning sky, it will begin around in front of the Sun again. The Moon will really move in front of the Sun this time, not only will we have a New Moon in early October, but an annular solar eclipse, though it won’t be visible from here in Ireland unfortunately. Once we’re through to the very end of the month, although we won’t have four visible planets in the morning, we will have three earlier in the night. Mars, Jupiter and Saturn will all be in the sky together at just a little after midnight, and of course Uranus and Neptune will be with them. We will also start to see Orion a bit after midnight, now that we’re getting back into winter those winter time constellations are going to be visible closer and closer to the middle of the night and we’ll see them more and more in the evening as we get later in the year.

Now that we’ve gone through the month in the city, it’s time to head out to the countryside. All of the planets will of course remain visible in the same places. There will be a partial lunar eclipse on the night of the Full Moon, and it will be a little easier to see in the countryside, but that will be dealt with next time, as it pairs up with the annular solar eclipse and together they are definitely enough for their own piece. Under a dark sky it is also easier to spot the shapes of some constellations, but some of the images that have been with us all summer are now falling out of view. Scorpius is already under the horizon by a little before 8 o’clock. If Scorpius is leaving the sky, the core of the Milky Way will be leaving our sky as well, though the outer portion of the Milky Way, such as the region passing through the summer triangle, that’s still going to be with us for a good portion of the early part of the night at least.

As we move later in the night, Sagittarius will be dipping under the horizon quite quickly as well, as early as just 9 o’clock. Uranus and Jupiter should be up by this time at the end of the month, and Mars will be crossing the horizon as we come up to 11 o’clock. Although they are visible from the city, they may be a little more obvious under darker conditions. The core of the Milky Way, most of it at least, has already set out of the sky by midnight at the end of September. Pushing onwards to morning time, Saturn will be about to hit the horizon as early as 3:30 in the morning, so that means it will be missing from the later morning sky. Neptune will be in the sky a little bit longer than Saturn, but not by very much. Saturn is going to reach its opposition just a few days before Neptune does, but of course with those distant planets, especially in the case of Neptune, the reason we are seeing them at opposition is because the Earth has moved into the correct position around the Sun to lineup with them. With the Earth, the Sun and those planets in a straight line, they will be with us all night and at their brightest just like a Full Moon. Neptune’s moving very slowly, as is Saturn, so changes in their apparent position day to day will mostly come from our motion, rather than their own, very different from planets like Mercury. Looking at the morning sky from the countryside, the Seven Sisters or the Pleiades, will be a lot more obvious, and they are a good indicator of roughly where Uranus should be. Just below them the Hyades with Aldebaran will be visible, and further down again we come to Orion. Being in the countryside lets us see fainter features such as Orion’s Sword. The Twins of Gemini will also be up a bit before sunrise, letting us see them in total darkness, and as the sun rises we can also see Leo. At the end of the month the Crescent Moon should be in Leo, which is after coming back into the morning sky. Leo would have been behind the Sun at least for the early part of August, but we can see here by late September it’s definitely back in view,

Pushing back towards the beginning of the month will bring Mercury back into the sky. You might be able to catch the smallest planet even as late as the 16th of September, but it will be getting out to its furthest from the Sun around the 5th. This date will give us the best opportunity to see Mercury, as early as 4:30 in the morning. the amazing vista of 6 planets, Mercury along with Mars, Jupiter and Uranus, with Saturn and Neptune further to the West, will look particularly good from the countryside. One reason that this is going to be an amazing view is because there is a slight chance that Uranus might actually be visible if your eyesight is good enough, potentially letting you see 5 planets, though 4 is more likely. Earlier in the night, while we are at the beginning of the month in the countryside, we can see that Orion is only going to up in the morning. Even at 2:45 it’s just barely above the horizon and once we get past midnight it will definitely be under that horizon,

Moving back to sunset we can see some differences from the end of the month. A little bit more of the Milky Way will be visible early in the night early in September. Mars will be low enough in the sky to get extincted by the atmosphere, this just means it will look fainter, just a little before midnight. At the beginning of the month, a little before midnight at least, we can see quite a few planets, we’re just missing Venus and Mercury. Venus of course will be missing for the month, we’re not going to see Venus in the sky at the same time as all of those other planets. Not this time at least, but having 7 planets up at the same time has happened before and I’m sure it will happen again in the future. As the Sun sets, with enough light for it’s glow to block out fainter objects, we will still have Saturn in the sky and the bright red star Antares will still be above the horizon. However, the light of the Sun will obscure the Milky Way. By about 8:45 the sky should be dark enough for the galaxy to be visible if you’re in the countryside without the extra light pollution. Any earlier than that and the glow of the Sun is going to block it out. Of course as we move into winter time the core of the Milky Way will be more and more behind the Sun and therefore more difficult to see.

That is it for a quick run-through of the September night sky. There is a lot more happening, but if I went into too much detail it wouldn’t be a quick overview. As mentioned, we will have Saturn and Neptune coming to opposition, there will be a lunar eclipse, and just after the end of September an annular solar eclipse. I will take a closer look at those events in the next piece. While I was recording the above video, I debated dealing with the eclipses for later in the month, but I can let any readers here know that I will actually deal with them in just a couple of days. We also have the equinox, I have made videos before on the equinoxes and how they relate to the solstices. With the autumnal equinox is coming up on the 22nd of September, I may talk a little bit more about them in general.

I hope you enjoyed this quick preview of what we’re going to be able to see in the September sky. If you did enjoy it then I encourage you to like it, and you can support the creation of more content like this by subscribing to this website or my YouTube channel. Hopefully, I’ll see you back here again next time.