Caoimhín's Content

Today we are starting just as we started the last time, with sunset on the 3rd of March. This time, we are going to be looking at the lunar eclipse that’s happening on the 3rd of March, the one which isn’t visible from here in Ireland. Starting from Ireland at sunset, the Full Moon will be 99.8% full, as we go through the night, it drops down to 99.7 and eventually down to 99.4 as we cross into the 4th. If we come back a day, to the morning of the 3rd, the Moon is 99.9% full as the Sun rises. Earlier in the morning it drops down from 99.9 to 99.8, and down to 99.6 as we push back into the night of the 3rd. We don’t get to see the Moon 100% full, though we do get very close early in the morning of the 3rd. We’ll start from as close as we can get, with the Moon at 99.9% full just as it is setting in the morning.

We will get rid of the atmosphere and the ground so that we can keep following the Moon under our horizon until it reaches 100% full. When the Moon reaches 100% full, it won’t be visible from Ireland because it happens when it’s about 8:50 in the morning for us here in Ireland. As we are at 100% full, the Moon gets eclipsed, a total lunar eclipse even from our latitude in Ireland. The eclipse finishes up by just about 1 o’clock in the afternoon here in Ireland, before the Moon comes back up again. This is a very clear total lunar eclipse. The really dark part of the Earth’s umbra is visible coming across the Moon, the entire Moon is red. At the peak of the eclipse there’s no part of the Moon that’s only covered by penumbra. There’s no part of the Moon with that kind of bluish tint that the edge of the Earth’s shadow has, which can be seen earlier and later in the eclipse. The deep red portion of the Earth’s shadow is closer to the center of the Earth’s shadow, the very edge has a sort of blue-ish colour. The eclipse also lasts for quite a while, the Moon is entirely covered for a while. However, we’re not going to get to see this in Ireland. In order for anyone to see this, you need to be in the right location, the right part of the planet.

Before heading to the right location on Earth, we will head to the Moon and look back at the Earth to see what will be, from the Moon’s perspective, a solar eclipse. The Sun is going to be blocked out by the Earth, the Earth is going to get in between the Moon and the Sun. Even before the Earth blocks the Sun, various planets are visible from the Moon. Looking towards the Sun there is Saturn, Venus, Mercury, Mars, and the Earth just about to come in front of the Sun. The Earth takes up a much bigger portion of the sky from the Moon than the Moon does from the Earth. Due to this, as the Sun is passing behind the Earth completely, it stays behind the Earth for quite a while. Given that the Earth takes up a much larger portion of the sky from the Moon than the Moon does of the sky from the Earth, the ratio between the objects in the eclipse is very different. Compared to the Moon and the Sun appearing very similar in size, the Earth and the Sun appear very different in size.

Unfortunately, we can’t look at the Earth from the Moon to see what portion of it is directly facing the Moon. We can’t see which portion of the Earth would give the best view, as we would with the same view in a solar eclipse. There would be a similar problem if we go to the Sun and take a look back at the Earth If we go to the Sun and look back at the Earth, the Moon will be directly behind the Earth, so we won’t get to see the Moon. We’ll only get to see the location on Earth that is directly opposite where the eclipse will look best. For this eclipse, the Sun is shining on Africa and Europe. This means we want to go to exactly the opposite side, over to the Pacific, that’s where we should get our best view. Coming back to the Earth, we’ll go with the very middle of the Pacific, that seems like the most likely location for this to work. We’ll pull back our field of view so we can get a fuller view of the sky, the land and atmosphere are back. Zooming in on the Moon around midnight gives us a great view of this total lunar eclipse. From the very middle of the Pacific, we’re seeing the entirety of the lunar eclipse, we can see the shadow of the Earth moving onto the Moon and moving off of the Moon from this location.

Because lunar eclipses last so much longer than solar eclipses, they’re visible from a much larger portion of the Earth. Some regions will only see part of the eclipse, but that’s okay. Really, the bit you want to see is the peak, with the whole Moon darkened. Seeing the shadow slide on or slide off of the Moon isn’t really the impressive part. It is nice to see the entire lunar eclipse from beginning to end, but really seeing any complete and total portion of it is good enough. That’s going to be achievable from a large portion of the Pacific, much larger than the amount of the Earth that any given solar eclipse would be visible from. For example, we’ll hop over to the western coast of North America, and the Moon is in the Earth’s shadow, fully eclipsed. Quite a good portion of the eclipse is visible from that coast, we can definitely see up to the end of the eclipse. Coming back, the very beginning of the eclipse is visible as well, so this whole eclipse is visible from the western part of North America as well, with the entire Moon looking red. That’s one side of the Pacific, we’ll hop over to the other side of the Pacific as well. I think that the peak of the eclipse might be a little off the center of the Pacific, so it might look a little bit better from the west coast of North America, but we’re going over to the opposite side of the Pacific just to check the view of the lunar eclipse.

From either side of the Pacific, this eclipse is going to be visible looking roughly from Japan, certainly at its peak. Moving a little further forward in time, the eclipse comes to an end, still completely visible. From the ending, we’ll move back in time to see if we can get back as close as the beginning. We can get all the way to the beginning of the eclipse, so the complete total lunar eclipse is visible. Most importantly, the entire Moon looks red at the peak, a true blood Moon. As the Earth’s shadow slides on and off the Moon, the fainter penumbra is also visible. From this location, we’ll come back to sunset when the Moon is fully clear, without any portion of the Earth’s shadow on it, completely exposed to the Sun. As we move forward,the penumbra will slide onto the Moon. The Moon’s absolute magnitude is indicated as 0.21, and we’re seeing it at about magnitude -13. This means the Moon really isn’t that bright, compared to stars for example, but we’re seeing it particularly bright because it’s particularly close to us. If we move back to the eclipse, the Earth’s penumbra will come onto the Moon, which will bring down the apparent magnitude, how it actually looks in the sky. As this happens, technically the numbers get smaller and these are negative numbers, so they’re getting closer to zero, which in this case means that it’s getting fainter.

If we keep moving, all of the Earth’s penumbra will cover the Moon, and then the umbra will make contact, bringing down the brightness of the Moon even more until it’s completely in the Earth’s umbra. At the peak of the eclipse the Moon drops to magnitude -1.5, for a difference of 12 magnitudes. These are usually stellar magnitudes, this magnitude scale that we use for measuring the brightness of things in the sky. Of course, this is lunar magnitude, really, because we’re looking at the Moon, but it’s all the same scale. Either way, it’s after getting much fainter. It’s still visible, there is still light, this kind of reddish glow that’s passing through the Earth’s atmosphere is reflecting back so there’s still light coming from the Moon, it’s still going to be visible compared to the blackness of space. From the pure Full Moon at a full -13 magnitude, very bright, the penumbra coming onto the Moon reduces it down to just about 12 and a half, and then the umbra reduces it down way, way further. Once the last bit of the Moon gets blocked out by the umbra, there’s a precipitous drop from about magnitude -10 there, let’s say even here, magnitude -9 with a tiny sliver of the Moon still visible, magnitude -8 with a sliver of the Moon still visible, and then suddenly it drops down to a magnitude -1, much, much fainter.

This is the lunar eclipse coming up early next month. This is the lunar eclipse that we’re going to miss from here in Ireland, because it’s happening for us pretty much in the middle of the day. It’ll happen, at just about 9 o’clock for Japan, from the middle of the Pacific at the peak, it should be happening at exactly midnight, and for North America it will be closer to morning time. For us here in Ireland, that means it’s happening at nearly exactly midday.

I hope that you get to see this lunar eclipse, it does seem like it will be a particularly good one. If you don’t get to see this lunar eclipse don’t worry, you already know what will happen thanks to the description here. If you enjoyed 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.