The Halloween Night Sky

As we welcome back the colder weather we are also welcoming back the beginning of the best months of stargazing thanks to the onset of longer dark evenings. Mix this with the spooky objects visible in the crisp autumn month of October and we have a recipe for fun and spooky nights of stargazing!

 

Where to see Cetus (Image credit: Kerry Scullion/AOP)

Where to see Cetus (Image credit: Kerry Scullion/AOP)

 

By the end of October we should have darkness by 7.30pm so we can start our winter stargazing pretty early compared to the summer, but personally I like to leave my stargazing to the later time of 10pm, just to make sure it is extra dark! There are not just the spooks and ghouls in the dark but also the wonders of the autumn night sky!

One of the best bits of advice for stargazing is that you need your celestial anchor for each of the stargazing seasons, and in autumn it is the Great Square, which is the belly of the mythical favourite, Pegasus! The four corner stars of Pegasus form an easily identified square shape and can direct you to various constellations and objects visible in the autumn night sky. So let’s use the Great Square to help find a few “monstrous’ constellations and celestial objects in the autumn night sky.

If we move to the east from the great square of Pegasus and look low to the horizon we can find the huge constellation of Cetus the sea monster! If you are anything like me, Cetus being a monster found the sea just makes it all the more terrifying! Cetus is also known sometimes as the Whale but I have yet to see a whale with terrifying front claws and a fear  inducing face to match! As the 4th largest constellation in the night sky kit has lots to offer the autumn stargazer with lots of bright stars and deep sky objects to try and spot. The brightest star in Cetus is Diphda (Beta Ceti), sometimes known by the traditional name Deneb Kaitos which means “the whale’s tail” (confusingly Iota Ceti is also sometimes called Deneb Kaitos). Whatever humans want to call it, this giant orange coloured star is located approximately 96 light years away from us and has a bright magnitude of 2.0. But this star is not the “star” of the constellation, the most famous star in Cetus is the variable star Mira, which means the “amazing one”. It rightly earns its name as many would class Mira as the most impressive example of a variable star. Located 420 light years away, this red giant star is one of the coolest stars known with a temperature of 1800˚C. As a variable star it is most impressive as during its cycle of 332 days it will range from a tenth magnitude star to a third magnitude star. The brightest it was ever recorded at was the magnitude of 2.0! Essentially it can sometimes be spotted very easily to being barely visible at all!

 

M77, a gorgeous grand design spiral galaxy seen face on. (image credit: NASA, ESA and A. van der Hoeven)

M77, a gorgeous grand design spiral galaxy seen face on. (image credit: NASA, ESA and A. van der Hoeven)

 

Using a small telescope you can also try and spot the beautiful, face-on, barred spiral galaxy Messier 77 (M77). It is located 60 million light years away and through a small telescope it will look like a star like point but with a hazy eclipse of light surrounding it. It has a very bright central region which leads astronomers to believe it to be a Seyfert galaxy, a galaxy that has a black hole at its centre that is highly energetic and a bright compact core with strong infrared emissions. It is a deep sky object definitely worth trying to spot.
 
 

 

 

I want to bring us next to try and find the beautiful constellation of the Swan, Cygnus. If we travel a little above the Great Square and then move a little to the West we can find the bright cross shape of Cygnus. Now I know what you are probably thinking, swans are not monsters! But a celestial object within Cygnus definitely falls with the “monster” category! It is the vampire star SS Cygni! SS Cygni is a binary system of 2 stars. One is a compact white dwarf star and the other is a larger star with about two thirds the mass of the sun. The  two stars orbit each other every 6 ½ hours and this means they are quite close to each other and it is here we see the white dwarf take on its vampire like role! The compact white dwarf gravity feeds on the larger star allowing the material to flow from the larger star to the white dwarf, this process (animated in the movie above)is called accretion but to me it slightly resembles the Sanderson Sisterssucking the lives out of little children” in the 1993 classic kid’s movie Hocus Pocus!  (Maybe we should call these binary system’s Sanderson stars instead!) What is impressive about SS Cygni is that every few weeks it is visible because it goes into outburst; this is like eating too much food and actually bursting except this is much brighter and less messy, but albeit, very violent! So get the binoculars out and try to spot this dramatic celestial object. Once in outburst it will take a few days to reach the magnitude of roughly 8.0 which is bright enough to be seen with a pair of good binoculars.

 

NGC 6543 (image credit: NASA)

NGC 6543 seen in an image created by combining visible light lights from the Hubble Space Telescope and X-ray images from the Spitzer Space Telecope. (image credit: NASA)

 

Since we are at Cygnus, let’s use the celestial swan to direct us to the monstrous dragon of the night sky, Draco! Located just to the west side of Cygus, this wingless beast has a very feline hidden treasure, the deep sky object NGC 6543 or the witchy, Cats Eye Nebula! This is stunning planetary nebula located 3,000 light years away. It can be seen by a small telescope but if you do look at it through a small telescope it will not be so clearly cat-eye like but rather a spooky blue/green hue that’s quite fuzzy. It is regarded as one of the complex planetary nebulae ever seen and is estimated to be roughly 1,000 years old which is not much with regards to the lives of stars. Astronomers use nebulae like the Cat’s Eye Nebula to study the process of the deaths of stars. So even though it is at the end of its life, we are still learning from its beautiful destruction.

Now we cannot finish up this spooky tour of the October night sky with mention of the werewolves’ favourite object, the Moon! If you wish to get good clear dark skies choose a night when the moon is not at its fullest. In October 2016 we have two New Moons, at the beginning of the month on the 4th of October (night of our first stargazing night of the season here at the Planetarium) and also at the end of the month on the 30th October. The Full Moon occured on 16th October, so I hope you avoided stargazing on this night as you would not have been able  to see the more deep sky objects, but you might have seen some fluffy werewolves!

(Article by Kerry Scullion, Education Support Officer)

 

 

Save

Save

Save