So summer is officially over so goodbye to the long bright evenings and short warm nights and hello to autumn with its optimal night sky viewing with the longer nights.Everything is just right.It is the Goldilocks of the stargazing seasons; we also have some of the joys of the summer sky still visible within the month of September so let’s delve in and try and see what we can find.

Image of Saggitarius nebulae

September’s Sagittarian Sights (Image credit:Kerry Scullion/Armagh Planetarium)

September is still a great time for gazing upon our home galaxy, the Milky Way and with the longer darker skies we may be able to see more clearly the celestial jewels hidden within it.  Our first mission is to find the Milky Way galaxy and nicely it is running right over our heads at this time of the year. A convenient way of finding the galaxy is to find the mythical centaur Sagittarius who points at the galaxy. But the best was to spot this constellation is by searching for a teapot in the southern sky close to the horizon. Once you find this stellar teapot, notice the galactic steam rising from its spot and your eyes will be resting on our home galaxy, the Milky Way.  Don’t be surprised if the Milky Way does not appear to be the easiest galactic treat to find, for most people the Milky Way is a relatively dim object due to today’s light pollution but if you can give your eyes twenty minutes to adept to the dark sky and find a relatively dark stargazing location you should be able to make out our home galaxy.

The Milky Way provides many stellar treats this month so take advantage of the darkening skies in September.First up let’s search for a celestial cloud in the sky, Messier 8 or the Lagoon Nebula. It is visible to the naked eye on a clear dark night, with some effort of course and shines at a relatively dim magnitude of 6.0, but if you can get your hands on a pair of binoculars you’ll clearly see its bright nucleus. And as an extra little treat for finding the Lagoon nebula, if you look to the left of it you will see the open cluster NGC 6530, shining at a brighter magnitude of 4.6, these 100 bright stars are stellar babies as this is one of the youngest known clusters known at just 2 million years old!

So moving from the west of the Lagoon Nebula sweep up a little to the north and search for a hazy patch of light surrounding a very dim star, you will actually need a telescope to pick up this hazy patch but once you do your eyes will be resting on the Trifid Nebula or M20, named thusly due to the three dark dust lanes running through it. This is definitely much more difficult to spot at a dim magnitude of 9.0 but with binoculars or a small telescope you will see this smudge of cosmic light in the sky that contains roughly 70 stars, covered in dust and gases.

Image of Jupiter_by_Cassini-Huygens

A regal portrait of Jupiter from the Cassini probe’s flyby of the giant world.(Image credit:NASA/JPL)

With the end of the summer and onset of autumn we can anticipate more reasonable hours to view some planets in the night sky as they begin to creep out of the daylight and return to the darkness.In particular Jupiter makes a blazing return with some picturesque moments to gaze upon.So to find Jupiter we really should pin point the pattern in the sky that will be home to it during September and the constellations don’t disappoint with the solar system giant resting in the object rich pattern of Taurus the Bull. To Find Taurus face North-East and close to the horizon you should spot and orangey giant of a star which is quite bright marking the fiery red eye of the bull,Aldebaran. This giant orange star is a bit like a stellar disco ball as its outer layers pulse without any recognisable pattern so its magnitude varies by 0.2 giving it a magnitude of 0.85, variable of course. Aldebaran marks the base of the left horn of Taurus and if you follow this horn to the tip and look slightly to the right we can see one of the most famous supernova remnants in the sky, the Crab Nebula or M1. It was first spotted by British astronomer John Bevis in 1734 and it is the expanding remnant of a massive stellar explosion that people around the world recorded happening in 1054 AD, most notable by Arab and Chinese astronomers.  At the centre lies a pulsar that rotates roughly 30 times every second. At nearly 6500 light years away from the Earth we should be thankful it is nowhere near us as it one of the strongest persistent sources in the sky. It’s not hugely bright at a magnitude of +8.4 but binoculars or a small telescope is defiantly going to let you glimpse the beauty in the sky.

image of Taurus nebulae

Telescope targets in Taurus ( Image credit:Kerry Scullion/Astronotes)


M1 is not the only magnificent object you can see in Taurus, if you make y our way back to the fiery red eye of the bull and move east to the shoulder of the bull you should easily catch the ‘Seven Sisters’ of the sky, the Pleiades Star cluster. Aldebaran literally translates to meaning the ‘Follower’ because it appears to follow this beautiful cluster across the sky. It perhaps one of the most famous open clusters in the night sky and are circulated throughout many cultures. In Greek mythology they are believed to have been seven sisters thrown up into the sky to protect them from the advances of Orion the Hunter. On a clear night you will spot about 6-7 of these bright blue and white stars but there are more than 100 in total in this stellar nursery, all ageing about 50 million years old!

But let’s get back to finding the Solar System giant, Jupiter. If you have managed to occupy your time searching for the Aldebaran you may have mistaken something much brighter and close to the orange giant  to be the fiery red eye, if so you may have been looking at the planetary god. To the east of Aldebaran you will see a brighter star like object but this is Jupiter and at around midnight in the sky he makes a triumphant return to the night and on  1September he will be shining at a bright magnitude if -2.2 and by the end of the month it will be a bright -2.4 and if you can get your hands on binoculars or a small telescope you should clearly see its four Galilean moons; Io, Europa, Ganymede and Callisto. Also throughout the summer Venus has dominated the early morning sky and will do the same this month so with this planetary Goddess you will still need to set the alarm clocks early to take in her bright and beautiful sight.

Image of Galilean Moons

Magnificent Moon Montage showing (left to right) Io, Europa, Ganymede and Callisto.(Image credit:NASA/JPL)


For all you moon gazers out there you will have to wait until the end of the month until the Full Moon on the 30th but there are definitely some picturesque moments this month, especially when the last quarter moon will be hovering to the left of the bright planet Jupiter on 9 September although it is definitely not advisable to try and spot our deep sky objects on this night as the light of the moon will make it very difficult to have any success.

September is packed full of stargazing wonders and throughout our deep sky object hoping you are sure to come across some extra celestial goodies to gaze upon.

So fingers crossed for clear night skies throughout September to ease us back in to those colder but darker nights.

(Article by Kerry Scullion, Education Support Officer)