Caoimhín's Content

Today we are going to look ahead to the end of August to see a lunar eclipse. Firstly however, tomorrow is the solar eclipse, the solar eclipse that I have been talking about at least all year. Here in Ireland, we will get to see a 97% total solar eclipse if you are on the western edge of Ireland, down in Kerry for example. Here in Cork City, we will see 96.4% of a total eclipse, which is quite a lot. Other areas in Europe will mostly see less. Unless you’re in Spain, Iceland, Greenland or Portugal, you’re going to see less than this.

Tomorrow is also the peak of the Perseid meteor shower. When I say tomorrow, really I mean after midnight tomorrow, into the next day, but I think it’s easier to just say go out on the 12th and wait until after midnight. We should see quite high rates from this meteor shower. If you would like to learn more about the solar eclipse and this meteor shower before they happen, check out some of the previous posts on this website, because in this piece, as I mentioned, we’re checking out the lunar eclipse that’s coming up on the 28th of August. Taking a look at that night, around midnight the Moon is pretty high in the sky. We’ll move back to look at the Moon just as it’s rising. Back on the 27th it’s up to 99.9% full, and if we move forward to the 28th, it goes down to, to 99.5%. That means sunset on the 27th is closer to the Full Moon for us, even though we’re only seeing 99.9% as it rises. If we move forward, hopefully it will go up to 100% over the course of the night, because of course the Moon has to be a hundred percent full, directly behind the Earth, to enter into our shadow and give us a lunar eclipse. In this case, it is partial lunar eclipse.

Firstly, the Earth’s penumbra, the very edges of our shadow, crosses onto the Moon, and then our actual shadow. Of course, this is a partial eclipse, so the entirety of the Moon is not being covered, even though the Earth’s shadow is much larger than the Moon. In this instance, the Moon isn’t close enough to the center of our shadow. Our shadow is so big that the Moon doesn’t even have to cross the exact center of our shadow to produce a total eclipse of the Moon, as long as the Moon is totally occluded by the Earth’s shadow, it is a total lunar eclipse. Unfortunately, a partial is the best we’re getting on the 28th, after midnight on the 27th.

As a partial, the Moon isn’t completely dark, there is a little bit of brightness sticking out the side. There doesn’t seem to bea degree of obscuration being given, but quite a lot of the Moon in our shadow. The Earth’s shadow isn’t completely dark because some of the Sun’s light is able to pass through our atmosphere. After being refracted and diffused by our atmosphere, only red wavelengths are left to impact the surface of the Moon, leading to the red or blood Moon. However, there is a little bit of a bluish gray shadow on the edge, between the deep red and light grey Moon. That’s some of the Sun’s light being diffracted by the edges of our upper atmosphere and the ozone layer, rather than being diffracted by the majority of our atmosphere, the oxygen-nitrogen mix that we have down here on the surface. This shadow produced by a more diffuse area of the Earth’s atmosphere does look a little bit different, but that is still the true shadow of the Earth, the umbra.

There is a partial shadow, or penumbra, of the Earth which is covers the Moon first, but it is difficult to see. After the obvious red shadow moves off the Moon, the Moon remains dimmed until a second, fainter shadow moves off. There is a difference between the Moon completely unobscured, as it is before the eclipse begins, and after the penumbra moves onto the Moon, but before the red shadow. So this is a partial obscuration of the Moon, but the Moon is darker in this partially obscured state then in the fully unobscured state. then the true shadow or umbra moves onto the Moon. It looks like we’re getting about the peak of this partial lunar eclipse just as we come up to 5 o’clock in the morning, so that’s when the eclipse will look best. A good portion of the Moon is covered even at 4:30 in the morning. The beginning of the eclipse proper, the Earth’s actual shadow moving onto the Moon is just about here at 3:30. The penumbra of the Earth is sliding onto the Moon at just about 2:20. This eclipse for us is happening very close to morning time. There will be locations on Earth where this eclipse is happening closer to midnight and of course it is going to look a little bit better from those locations.

The eclipse occurs as the Moon is setting for us, and the Sun is rising. Just as the eclipse reaches its maximum, that obscuration is happening while the Moon is over towards the west. So westwards is where we need to go. We will hop over the Atlantic simply because not many people will be viewing this from the center of the Atlantic. We’ll jump over here towards the Great Lakes, the eastern edge of the Great Lakes closer to Ireland, and we’ll take a look at how obscured the Moon is. It is as obscured as the partial can be at just about 11 o’clock, 11:10. Let’s move back here a little and see where it really peaks. At just before 11 o’clock coverage still seems to be increasing just a little bit, and then it begins to decrease. I think that the peak is at just about 11 o’clock, not quite 11:10. The Moon about as obscured as it’s going to get and we’re seeing it so close to midnight.

The Moon is almost directly above the south, but I think it may improve just a little bit more if we move. It would improve if we moved a little further east, just into the Atlantic off the coast of North America. Bermuda doesn’t come up in Stellarium, but the city of Hamilton does. Around Bermuda, one corner of the Bermuda Triangle, it looks like the Moon is at its highest in the sky at just about the right time. At just a little past midnight here, almost at 1 o’clock, the Moon is pretty much as obscured as it’s going to get. If we move a little lower on the planet, into the Caribbean and onto South America, the amount of the eclipse doesn’t increase. Down in the southern hemisphere things appear upside down compared to what we’re used to here in the north, but the amount of the eclipse isn’t increasing. It is still quite a lot of an eclipse, there is still a good portion of the Moon covered.

As we move further and further east, we can see it happening earlier and earlier. the Peak is at just 8:20 in the evening pretty much in California. If we come back towards Ireland again, it’s about 5 o’clock in the morning once it peaks. So of course it is peaking at very different local times from different locations around the Earth, but we can see that the degree of eclipse is pretty much staying the same. This is visible from large portions of the Earth, it is getting very close to morning time even as we move a little bit into Eastern Europe, but all along Western Europe, North Africa and the Americas, this lunar eclipse is going to be visible. It looks like it might be just out of view once we wrap around to the other side of the Pacific, even from the center of the Pacific it is underground. That is the lunar eclipse that is paired with the solar eclipse that we are getting this week.

We’ll get rid of the atmosphere, the ground and we will bring up the line of the ecliptic. The ecliptic line is an imaginary line in the sky, it’s not imaginary per se, it’s not so much that it’s imaginary as that it is created by people. This is a “man-made” line in the sky, based off where the Sun’s equator would be projected out into space. Really, it is a circle rather than just a line. Looking along the ecliptic, we have Saturn, we have Uranus, we have Mars, we have Jupiter, we have Mercury and we have Venus, all pretty close to the line. Of course we have the Sun and then we have the Moon. The Moon and the Sun are on exact opposite sides of this line during the eclipse. The Moon is on the ecliptic, which means it is in our shadow. The Moon can cross the ecliptic at other times, but if it’s a Full Moon, it needs to be directly behind the Earth. As we move through time, moving back to the solar eclipse, the Moon goes below the ecliptic. It doesn’t stay on it because the Moon is following our equator rather than the Sun’s. Once we come up to the day of the eclipse, of course, we’re in the middle of the night, so we’re not at the time of the eclipse, but we can see the Moon moving back onto the ecliptic.

This is the Moon’s path across the sky. As the Moon moves across the sky, it will move across the ecliptic, but it does not follow the ecliptic as the Sun does across the sky and throughout the year. The Moon comes onto the ecliptic to cross onto the face of the Sun for the eclipse. If we move back, the Moon ends up pretty far from the ecliptic as it wobbles through its phases. Then it comes back up to the ecliptic to move into our shadow, more or less at least. The eclipse will be just as the Moon crosses the ecliptic. Now, of course, this isn’t a perfect eclipse. If the Moon was crossing the ecliptic just a little bit further along, it would be a total eclipse, but because this cycle isn’t perfect here, the Moon is going to land a little bit off our shadow. When it comes back around to new next month, it will cross a little off the Sun and it won’t cause an eclipse. This will progress, it will move its crossing points along the ecliptic as it moves crossing at a slightly different phase. Eventually it all lines up again, and for the solar eclipse that’s going to be in August 2027 in Spain and North Africa, into the middle east.

We have this lunar eclipse coming up at the end of the month. Tomorrow, of course, we have the solar eclipse. I hope you get to see both of them and the Perseid meteor shower. I hope that you enjoyed this piece, if you did then please do like it and 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.