What’s In The Sky: Autumn

As the leaves turn brown, and the days turn cold the nights draw in fast over autumn, making it a great time to head outside and stargaze.

Autumn is a fantastic time to do some stargazing, as we leave the summer it usually remains warm enough that the weather doesn’t keep us from heading outside. Autumn also has the benefit that it starts to get darker earlier. So, you don’t have to stay up too late to get a fantastic view of the stars.

The autumnal sky sees the rise of some people’s favourite constellations and objects, so let’s have a look at some of the season’s highlights.

Cygnus - The Swan

Cygnus is a great constellation to spot in the autumnal sky. It lies roughly north west as sits across the Milky Way. In very dark areas these faint clouds of stars can be spotted as a back drop to this constellation. Cygnus is easy to spot, containing fairly bright stars. It also contains an easily recognised pattern of stars known as the Northern Cross.

The constellation of Cygnus features prominently in many different cultures’ mythology. The Greeks associated two different stories with the figure of the swan in the night sky. One was a disguise of Zeus and the other tells the tale of Phaethon, son of Helios.

In this story, Phaethon loses control of his father’s chariot resulting in him ending up in the river Eridanus (another constellation). Phaethon’s brother then spent many days searching the river for Phaethon’s remains. The gods were so impressed by his dedication that they transformed him into a swan to make the search easier.

The constellation of Cygnus contains a whole host of deep sky objects to investigate. Not only are there a lot but there is also a huge variety, from open star clusters to nebulae and giant stars. One of the most visible is the North America Nebula. This huge cloud of gas sits close to the brightest star in Cygnus, Deneb, which marks the tail of the swan. The nebula gets its name from its shape – the swirling clouds of glowing gas form a shape very similar to the continent of North America, complete with the Gulf of Mexico. This shape is caused by a band of dust that lies in between the Earth and the nebula itself, which absorbs some of the light to give us the distinctive shape.

Cetus - The Sea Monster

Cetus could be considered to be one of the most terrifying constellations in the sky!

The constellation we know as Cetus was originally documented by the ancient Greeks as the representation of a great sea monster. In the Greek tales this sea monster was closely linked with a whole host of other constellations found in the sky. Cetus was sent by the God of the Sea, Poseidon, to destroy the lands of Queen Cassiopeia. She earned his wrath through a declaration that her daughter, Andromeda, along with herself were more beautiful than Poseidon’s daughters. Andromeda was offered as a sacrifice to calm the monster but the Greek hero Perseus intervened, killing Cetus and saving Andromeda and Cassiopeia’s lands. All of the characters but Poseidon have a constellation described in the sky, making this a great tale to help stargazers navigate their way around the night sky.

Not only does Cetus offer a great opportunity to explore Greek mythology it also offers astronomers a great place to look in the night sky. The constellation of Cetus faces away from the plane of the Milky Way, meaning that distant galaxies aren’t blocked by our own. The lack of dust obscuring the view means stargazers can get excellent views of galaxies. The brightest of these is Messier 77, a face on spiral galaxy. As it is face on, we get a fantastic view of the spiral structure. Images of the galaxy clearly show the spiral arms as well as the bright nucleus of the galaxy. Being able to see galaxies like this allows us to gain a strong understanding of how galaxies work. Evidence shows that our galaxy is almost certainly a spiral one. So observing other spirals, like Messier 77, gives us a great view of what our own galaxy could look like.