Caoimhín's Content

Today we are going to take a look at a few eclipses that challenge the eclipse of the century, that we will be getting next year, in terms of duration. One of these did already happen this century, but we’re going to look at an even longer, older one first. With regards the title, over on YouTube I decided to test two alternate titles for the video, so I’m providing both here for completeness.

We will begin by looking back to the year 743 BC or 743 BCE, whichever term you prefer. Even from here in Ireland, the New Moon is clearly almost in front of the Sun. This eclipse is a historically very long eclipse, and we’ll take a look at its maximum duration soon, but as we can see here from the dates, this eclipse isn’t this century, so our eclipse of the century, the very long eclipse coming up next year in 2027, is still at least one of the best eclipses we’re going to get this century. This older eclipse, based on the records I have been able to see, had a much longer duration, but it wasn’t visible from here in Ireland. We can go through a little bit of time to check this, and as we do the Moon is completely misses the Sun. We’re definitely not getting this eclipse from here in Ireland. According to the records I could find, this eclipse was best visible from just off the coast of the Horn of Africa, just off the coast of Somalia. This is quite close to the equator and quite close to the subsolar point. Also, it’s n July. The eclipse that’s coming up next year is going to be happening in August, so even though we are going to be close to our aphelion, close to our furthest position from the Sun, this eclipse occurred when the Earth was even closer to aphelion, even closer to our furthest position from the Sun.

From the correct location, really still a few kilometers off but that’s really not too bad, at 100% obscuration the duration is over 7 minutes. This is very close to the absolute maximum that an eclipse can be. Zooming in to take a closer look, the Moon is perfectly covering the Sun. Taking a look at our distance to the Moon, it’s just over 352,000 kilometers. This is very close to the Moon’s perigee. Just like the very long eclipse, the eclipse of the century, that is coming up next year, it’s going to look particularly good because we’re at our furthest position from the Sun, which means the Sun will appear its smallest in the sky, (not that we should ever look directly at the Sun) and the Moon is at its closest to us so the Moon will appear its largest in the sky, even closer to its perigee for the 743BC eclipse than the 2027 one. These are the factors that line up to make these eclipses very long, and as we’ve been able to see, this eclipse period is at 7 minutes and 24 seconds at its peak. Almost 7 and a half minutes of darkness, so a whole minute longer than the eclipse of the century that we’re getting next year.

Of course, this eclipse was centuries and centuries ago, so even though it is longer than the eclipse of the century we’re getting this year, this eclipse didn’t happen this century, so we don’t really have to worry about it. It is better than the eclipse we’re getting next year and better than the eclipses we’re getting this year, however it can’t be our eclipse of the century because it’s not in our century, it was so long ago. As usual, this provides a fantastic level of darkness right in the middle of the day, and there’s so much we can see. Sirius is very clear, we’ve got Orion visible as well, we’re down in the southern hemisphere so of course it does look a little bit upside down. We’ve got Mercury, we’ve got Venus, all of these things that we’d expect to see during an eclipse. This isn’t the longest eclipse that I’ve been able to find, there is an even longer eclipse coming up in the far, far future, but there was also quite a long eclipse already this century.

We are still going into the past here, but not very far, just back to 2009 and we’re looking ahead July 22nd. Again, this is very close to our aphelion and we can tell we’re at the right date here because the New Moon is almost in front of the Sun. This time of year, even though it’s the hottest time of year in the Northern Hemisphere, it is the time of year when we’re furthest from the Sun. Earth’s orbit is elliptical, so we do have our closest and furthest positions from the Sun, but the difference between our closest and furthest positions is so slight that the tilt of the Earth still has a much, much greater influence on how hot it is here on Earth. Whenever the Northern hemisphere is tilted towards the Sun, even if we are further from the Sun then than we are in winter, it’s still going to be that little bit hotter. We are heading over to the Pacific, just a little south of Japan, aiming for the island of Iwo Jima. This is the location where this eclipse is supposed to be at its best, but of course, we might need to hop around a little bit to get it at its exact maximum, the exact totality.

I had some issues with this in previously, finding the exact right location and having to mess with the latitude and longitude to make sure that we were in the exact right place. However, I do believe that there is another way. What we’re going to do is take a look from our Moon. We’re going to look from just next to the Sea of Tranquility because that is the place that will be facing roughly towards the Earth. Looking back at the Earth, we’re going to look and see where the shadow of the Moon is. It’s a little bit cloudy, but it looks like we’re definitely above Australia and under Japan. By moving through time, the exact darkest part of the eclipse moves around, giving us an idea of where the eclipse path is. Hopping back to the Earth, we’ll try and get to exactly that location. Of course, if this doesn’t work, then I will double check the exact latitude and longitude. Unfortunately, by attempt landed me in a location where only a partial was visible. The Moon almost went around the Sun, covering part of it, and then sliding off to the other side. Luckily, I can use the actual latitude and longitude to go to exactly the right place. I was a little bit off, we want 24.2 North and we want 144.1 East. This 144 degrees and 1 minute of arc, and then 59.22 seconds of arc. The seconds don’t matter too much, seconds of latitude and longitude are quite small measurements,

Finally looking at totality, and we have a duration of 6 minutes and 39 seconds. So it is only a matter of about 10 seconds, 10 to 15 seconds, longer than the eclipse of the century, and this eclipse was just back in 2009, that was this century. Even though six minutes of darkness, really almost six and a half minutes of darkness, it is very impressive, and we have that coming up in 2027, calling it the eclipse of the century may be a little bit of a misnomer depending on how you judge the eclipses, because the 2009 eclipse had a longer duration. In 2009 the Moon was pretty much at its perigee for this eclipse, just over 351,000 kilometers away from us, and at the right time of year to be pretty much at our aphelion. All the factors line up once again to give us a very long eclipse, but in this case, just a little bit longer than in 2027.

This eclipse, as I mentioned, it already happened, it happened back in 2009, and there wasn’t as much fuss about it as we’re seeing for the eclipse of the century that’s happening next year in 2027. So many people are talking about the eclipse of the century that we haven’t even heard that much about the total solar eclipse that’s coming up this August in 2026, which is going to be visible from parts of Europe. One possible reason is that the path of the 2009 eclipse was mainly over the Pacific, areas where there aren’t as many people living. Conversely, the eclipse that we’re getting next year in 2027, its maximum is just going to be around the Red Sea by Egypt, and that’s going to be visible by a lot more people. Even though the 2009 eclipse, just a few years ago, was longer in duration, the eclipse that we’re getting next year is going to be visible by more people, and it is only a difference of 10 seconds. Being strictly accurate about it, we’ve already had our longest eclipse of the century, but the best eclipse of the century, the eclipse that most people are going to enjoy, that is most likely to be the one coming up in 2027.

We’ve spent a little bit of time talking about these eclipses, so I don’t have time to take a look at the even longer eclipse coming up in the further future, we’re going to leave that one for another day. I hope that you enjoyed this piece, I hope that you enjoyed this comparison of the lengths of the eclipses, looking at even longer eclipses than the eclipse of the century which we covered in the last piece. If you did enjoy this piece, then please do like it. If you enjoy this kind of content, then please subscribe to this website and my YouTube channel. Thank you very much for reading and hopefully I’ll see you back here next time.