July 27, 2018 – Germany experiences a total lunar eclipse
During the holiday season, the sun, moon and earth have prepared an astronomical highlight for Central Europe and thus also for Germany – a total lunar eclipse. But what actually happens and does it happen frequently? That's what this post is about.
#MoFi2018 – The hashtag for the total lunar eclipse?
Like any event – whether elections (#btw17), sporting events (#RMAFCB) or campaigns (#weilwirdichlieben), the 2018 total lunar eclipse will also get a hashtag. Currently you can't find this hashtag on Twitter, but it will be, because with this article I'm putting this hashtag into the world for the second time. 🙂 I myself have also created an event on Facebook for the inclined reader of this article. There I will collect and distribute information at irregular intervals about this heavenly event. Everyone can feel invited and ask questions about the total lunar eclipse.
How does a total lunar eclipse occur?
Last year, a partial lunar eclipse was observed over Germany. At that time I was on holiday with my family in the Berchtesgadener Land. We came back from Salzburg and before we returned to our apartment, we could watch the rising moon over the Alps. Some photos were taken, which I do not want to withhold from you here. The question that determines this paragraph is: How does a (total) lunar eclipse occur? In order to eclipse the moon, a very specific position of the sun to the earth and the moon is required. The movement of the earth around the sun and the moon around the earth is of decisive importance. One can only speak of a lunar eclipse if the light of the sun cannot shine on the moon because the earth has "pushed" itself between the two celestial bodies. The following graphic illustrates this constellation wonderfully. If the Earth does not obscure the entire moon and the sun can illuminate parts of the moon, it is called a partial lunar eclipse. However, science distinguishes between four categories (clever people like to quote from Wikipedia, me too 😉 ):
Total umbra eclipse: In the total umbra eclipse, also called total lunar eclipse, the moon completely enters the umbra of the earth in the course of the eclipse. Since sunlight is refracted into the shadow cone by the Earth's atmosphere, especially long-wave red parts, the moon remains faintly visible as it passes through the Earth's umbra, as a so-called blood moon. The maximum possible duration of a total lunar eclipse is about 106 minutes. Partial umbra eclipse: Only part of the moon dives into Earth's umbra, the rest remains penumbra. The edge of the shadow cast by the earth is imaged on the lunar surface and visible as a circular arc, as well as at the beginning and end of a total (umbra) eclipse. From the circular shape of the shadow, the ancient Greeks already concluded that the earth was a sphere (overcoming the idea of a flat earth). Total penumbral finternis: The moon is completely immersed in the penumbra of the earth, but not in the umbra, whereby the part of the moon closest to the umbra is often noticeably darker. A total penumbral eclipse is rare because the ring of the penumbra is about as wide as the diameter of the moon and in the few cases where the moon passes almost appropriately through the penumbra, it may also be that it is slightly smaller than the moon. This is then partly outside the penumbra or partly inside the umbra or both; this leads to a penumbral eclipse, which is partial (see below), or to a partial umbra eclipse. The last total penumbral eclipse took place on March 14, 2006, the next of its kind is predicted for August 29, 2053. Partial penumbral finternis: The moon is only partially immersed in the penumbra. It is barely noticeably darkened. Only if the magnitude is greater than 0.7 can an eclipse on the side towards the umbra be reliably perceived with the naked eye.  A partial penumbral eclipse of the moon is relatively common; since its diameter is nearly as large as the ring of the Earth's penumbra wide, it occurs about as frequently as the partial umbra eclipse.
How long does the total lunar eclipse last?
With 103 minutes, the upcoming total lunar eclipse will be in the middle of the field. Because a lunar eclipse lasts between 100 and 106 minutes. All phases are considered. The lunar eclipses in 1988 and 2000 went over the full distance of 106 minutes, with the minimum of 100 minutes had to be satisfied in 1935 and 2011. In 2047, this spectacle will last only 100 minutes. So let's enjoy the three minutes of injury time on 27.07.2018.
Solar eclipse or lunar eclipse – which happens more often?
If you consider that in the 20th century 229 lunar eclipses could be admired all over the world and in the 21st century 228 of these celestial events are scheduled, that sounds like a considerable amount. But what about a solar eclipse? The 20th century held 228 solar eclipses for the world. in the 21st century, the Sun, Moon and Earth could only find 224 dates for solar eclipses. And so it is also clear that the moon is more often obscured by the earth than that the moon flicks the light out of us.
Was that it?
No, because I will bridge the time until the total lunar eclipse on 27.07.2018 with one or two more articles. If the inclined reader has questions, you are welcome to contact me here in the comment function or via the social media channels. For this article I would like to thank the Steffen family from Lebach. Here I could link the graphic to the lunar eclipse.