Welcome one and all to your favourite ‘happy place’ – the AOP night sky blog, where you can kick off your shoes, cosy up in a comfortable chair and chill-out amongst the shimmering stars! It’s also the month with the confusing name which begins with “Oct” -which implies the 8th month, but that we know is in reality the 10th of the year. This is easily explained when we go back to the original Roman Republic calendar which only contained 10 months in total, and of which October was the 8th. Apparently though, a chap called Caesar came along and added in 2 more at the start of the year, pushing our 8th month into 10th position. So without further ado let’s start our tour of the October night sky!
We’ll start by looking WEST, (the direction where the Sun sets in the evening) from 10pm onwards. The month commences no less than with a meteor shower, the Draconids, peaking on the night of the 8th through until the morning of the 9th October with up to 10 meteors per hour, visible around the constellation of the dragon, Draco – from where they radiate. (Being a ‘Circumpolar constellation’, one that revolves around and close to the ‘Pole Star’, Polaris – this meteor shower is guaranteed to hold a prominent position high above the horizon.) Although the Draconids tend to be one of the ‘lazier’ meteor showers of the year, as the sky continues to darken as we progress through the autumn months it could be well worth keeping your eyes peeled with this meteor shower because occasionally the dragon stirs from his slumbers to unleash numerous fireballs across our northern celestial hemisphere!
If the meteor shower proves to be a tamer affair -why not instead look for the glowing eyes of the dragon in the dark? These are stars Rastaban and Eltanin. To find them, locate the 2 distinctive asterisms – the Summer Triangle and the Plough. The dragon lurks between these two star patterns, with Eltanin, a 2.24 magnitude star being the closest and brightest just to the right (or north) of the star Vega. Draco’s other eye – the star Rastaban, is the third brightest of this star pattern and like Eltanin, is also a double star.
While we’re in the celestial vicinity the next object that’s a favourite among astronomers is, what’s believed to be the site of a galactic ‘hit- and-run’ accident! Being about 420 000 000 light years away in the constellation of Draco, it took no less than the Hubble Space Telescope to see the object clearly, as it’s much too dim for the naked eye. It lies in the curving belly of Draco where Hercules’s right knee comes closest to the dragon in the night sky.
An explanation for the unusual shape of this galaxy (called Arp 188) is that about 100 million years ago, a smaller more compact galaxy is thought to have ripped through the larger barred spiral galaxy (visible in the foreground), with tremendous tidal forces pulling out stars, dust and gas along the way. “So where is the culprit?” – you may well ask. Well astronomers think the smaller cosmic saboteur is impudently hiding about 300 000 light years behind its victim in Space! After its heinous act of cosmic sabotage, producing a bright debris trail 280 000 light years in length, forces of gravitational attraction between the two galaxies caused the ‘intruder galaxy’ to slingshot round behind Arp 188. Despite what occurred between these 2 galaxies in the past, scientists believe gravity has them destined to make up and ultimately merge some time in the future! Thanks to the unusual shape of this galaxy, it has been nicknamed ‘The Tadpole’. 
Let’s now swing round on our heels to look in the opposite direction to where the Sun rises in the morning, so that we’re facing EAST. The summer months have provided a great opportunity to enjoy all the splendour of the Summer Triangle and it’s associated constellations, but as we approach the mid-point of our autumn season – let’s now draw a few more triangles in the night sky. Just above Jupiter mid-month at 10pm you’ll be able to find the constellation of the ram – Aries. In mythology Aries was the magical ram belonging to Zeus, king of the gods and instead of wool its fleece was made of gold. The brightest star in this constellation is called Hamal which means ‘head of the sheep’. If you want to check you’ve found it, with your mind’s eye draw 2 lines out from the left-hand-side of the Great square of Pegasus towards a bright star to form a triangle. The star you should find should be Hamal.
Moving upwards is a small often overlooked little constellation called Triangulum, which, as the name suggests is another little triangle in our night sky. If you see a little group of stars between Aries and that super-bright ‘W’ in the night sky, queen of the heavens – Cassiopeia, then you can be sure you’ve found it. Although Triangulum is particularly small, within its celestial terrain is a real gem – the Triangulum Galaxy, M33, also sometimes called the ‘Pinwheel Galaxy’, because of its striking shape. It lies about 3 million light years from Earth and spanning more than 50 000 light years across is the 3rd largest star city in our Local Group of galaxies.
During the early hours of the 22nd October in the southeast, as he continues to rise above the horizon – Orion the hunter’s upraised arm will be bearing a giant ‘cosmic sparkler’ in the form of the Orionids meteor shower! Look out for 10-20 meteors per hour radiating from the Orion constellation on this date which is the meteor shower’s peak.
If you missed the impressive sight of a conjunction of the Moon and Jupiter in the east on the 2nd of the month (when 2 celestial objects ‘appear’ close together in the sky despite actually being separated by a great distance in the Solar System), then enjoy another conjunction of the second biggest planet of the Solar System – Saturn with the Moon on the 24th October!
And to round things off nicely the Sun, Earth, and Moon will be almost perfectly aligned on the night of the 28th October so that part of the Moon’s disk will disappear as it dips into Earth’s shadow for a partial lunar eclipse. Between 7pm and 11.26pm (in the UK and Ireland) watch out for the whole Moon darkening somewhat as it passes through the ‘Penumbra’ (zone behind the Earth where some of the Sun’s light can no longer reach). After this, a small part of the darkened Moon will look like it has disappeared as it skims the Umbra (region behind the Earth best hidden from all sunlight). Lending its support for this end-of-month extravaganza will be the king of the planets, Jupiter – flanking the Moon on its left-hand side. So keep your eyes peeled for the silhouette of a figure on a broomstick during this ghoulish Full Moon event!