Category: Astronomy Page 1 of 1

Alright folks, I know I was two days / three days late with this one depending on what time zone you are living in. So lets stick to the UTC time when this occured (September 28th 02:37 UTC)

On September 28th 2015 at 02:37 UTC, people in the Americas and parts of Europe and Africa were able to witness the Lunar Eclipse of a Super Moon, in which the moon turns a red colour (sort of blood red, hence the term blood moon), is full in appearence and is at it's closest to us within its orbit.

So let me explain in more detail what is exactly going on. The orbits of the planets around the Sun within our solar system, although are commonly thought of being perfectly circular within diagrams in textbooks or on the internet, in reality are not. All of the planets undergo elliptical (oval) orbits and within these orbits there is the Perihelion, which is the point at which the planet is closest to the sun, but also the Aphelion, which is the point at which the planet is the furthest away from the Sun. However there is very little difference between the Aphelion and Perihelion and thus the planetary orbits can be approximated as to being circular. These oval orbital paths rotate themselves around the sun too, so the furtherst and nearest point of the planetary orbit around the sun in physical space relative to the sun changes. This is known as a precession. Interestingly, and for another blog post, apart from the orbit of Mercuary, these can be calculated using purely newtonian forces. Mercuary is interesting since it's precession occurs at a faster rate than predicted from pure newtonian mechanics, and is thus a nice confirmation of Einstein's General Relativity.

Back on topic, the Earth and Moon system is very similar. You have the Moon orbiting the Earth in an (ever so slighty) elliptical orbit, with a Aphelion and a Perhelion. What constitutes a "Super Moon" is simply a Full moon (i.e when the moon is positioned behind the Earth relative to the Sun, and thus is illuminated by the sunlight and appearing circular and bright on the night sky), but the phase of the moon being full occurs at the same time it is at its closest point to the Earth. The "Blood Moon" or "Lunar Eclipse" simply comes from when the Moon appears red due to the refraction of light in the Earth's atmosphere when the Moon is positioned exactly behind the Earth.

So why don't we see Blood Moons all the time? Simply because the Moon's orbit around the Earth is inclined to the Earth's orbit around the Sun (i.e they do not orbit in exactly the same plane). So when you get the uncommon occurance of the Moon being behind the Earth, and thus red due to the refraction of light of the Sun, in addition to the uncommon occurance of Super Moon (in which the Moon is at it's closest point to Earth at the time of the Full Moon phase). You get a Super Blood Moon.Here is a picture that myself and my girlfriend Andrea took whilst we got the chance to see it ourselves in Cole Harbour - Canada - Nova Scotia. I know it is not the best of pictures. I might also include here some of the better Super Blood Moon pictures that I have seen on the web and by my friends too.

Hope you got the chance to see the Super Blood Moon too. Share your experience in the comments below. You need to register an account in order to reply to this blog post.


A montage showing the transition of the moon over various stages leading up to the total eclipse. Credit Peter Zelina


Lunar Eclipse image taken by Wolfgang Krispler


Image taken by cosmosquark

The picture taken by me was taken with a Samsung Galaxy S5

The other images are taken from .

As you can tell, best to take a picture with camera equipment that is better than your standard smartphone ;)

29 Sep 2015, 1:50 a.m. Replies: 0

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