With the summer well underway we can really delve into some of the summertime treats the night sky has to offer us.Although the duration of darkness in the summer nights is relatively short compared to the rest of the year there are still celestial treats to behold.There are some very interesting natural occurrences happening this month but they tend to favour the Southern Hemisphere so if you are finding yourself holidaying in the warmer continents of Africa or Australia you should make sure to pack your stargazing essentials.
July is also the month that we earthlings find ourselves at aphelion!In other words on 5 July at roughly 3.00 UT (Universal Time) the Earth was at its furthest point from the Sun, a distance of 152 092 400 km.Not something that you can physically spot but still an astonishing thought.
If you do find yourself relaxing in the Southern Hemisphere during July there is the return of the dim Comet Machholz (Comet 96P).It is quite difficult to spot but on the 14th it was at its brightest magnitude of roughly 9.0 whilst it reaches perihelion at only 0.12 AU from Earth. It will hopefully be the brightest comet of the year, but that’s not to say it won’t be a difficult object to spot in the Southern Hemisphere.
But moving on to what we in the Northern Hemisphere can see during this “tropical” July month!Well as already discussed in the previous stargazing month of June, summer is not the best season for stargazing but if you’re willing to keep your eyes peeled into the small hours then you can still see some fantastic wonders during summer, just be willing to accept a very sleepy day to follow.Some interesting constellations are not very high in the sky but instead they are hiding around the horizon, such as Sagittarius the centaur archer.From all of Ireland we can only spot the top half of him and to find him you search the southern horizon for a teapot within the mythical creature.This celestial teapot gives us a helping hand to discover the location of the Milky Way Galaxy which you will find rising out of the teapots spout!
During the summer months the Milky Way Galaxy runs right over our heads and will need some skill to spot as it is very faint, especially with all of today’s light pollution.It appears as a dusty smudged area of the sky that runs overhead from the South Horizon to the North Horizon.The Milky Way is classed as a barred spiral galaxy containing 200 – 400 billion stars!It’s also huge stretching across 100 000 – 120 000 light-years in diameter and it takes 200 – 240 million years for it to fully rotate once, that means since the extinction of the dinosaurs 65 million years ago, the Milky may has yet made a full turn.
The area rising from the teapot’s spout in Sagittarius is the centre of the Milky Way and scientists believe a supermassive black hole is hiding here, but no need to panic as it is too far away to cause us any wrinkles of worry!But this view of the Milky Way has multiple fantastic treats for us to behold, but binoculars or small telescopes will be need to enjoy them.Around the centre of the Milky Way Galaxy there is a beautiful halo of globular clusters, groups of a few hundred thousand stars with no gas or dust, just gravity and very old stars.Because we are looking into this direction in the summer months we can hunt for these beautiful, sparkling stellar groupings.Take for example M22 or NCG 6656 which is an elliptical globular cluster in the constellation of Sagittarius found near the Milky Way’s galactic bulge.It is one of the closest clusters to Earth, a mere 10 600 light years away and is the brightest cluster in the Northern Hemisphere with an apparent magnitude of 5.5 but it is very near to the horizon and seems less impressive than that of the higher rising clusters.We also have the more famous clusters which we have discussed in previous months such as M13 located within the Greek hero Hercules and another well-known grouping of aging stars, M3.Messier 3 is found in the west between the constellation’s of Bootës and Canes Venatici.Find Arcturus, the bright star of Bootës, and follow in across to the hunting dogs and two thirds of the way you will spot this beautiful cluster.Dimmer than M22 with an apparent magnitude of 6.2 its still better known as it is higher in the sky holding a more prominent stellar position and contains some of the largest and brightest stars.It has roughly 500 000 stars with an estimated age of 8 billion years, nearly double that of our Sun! Globular clusters appear as smudges, if that, to those with the best of eyesight on a clear night so to view these majestic beauties in the sky it would be more satisfying through binoculars or a small telescope.
Moving on towards some interesting constellations, especially for those of you who are just starting out are the circumpolar constellations.The North Star or Polaris found in Ursa Minor or the Little Bear, obviously, found in the northern sky always appears fixed in the sky due to the fact it is aligned with the Earth’s axis of rotation.That means the immediate patterns that surround it will forever chase each other around the Pole Star and never set below the horizon.So no matter what time of the year you want to see them, as long as we are graced with clear skies, they are visible.
The five circumpolar constellations include Cassiopeia the queen and her husband Cepheus the king, Draco the dragon, Camelopardalis the giraffe, Ursa Minor the little bear and finally Ursa Major the great bear. These constellations have some of the most interesting myths and legends due to their continued presence and position. The star Thuban in Draco the Dragon was the pole star during the era of the ancient Egyptians around 2700 BC and has multiple myths from several cultures.One very entertaining and interesting is the Chinese tale that shape of Draco the dragon would appear to be eating the Sun or Moon in an eclipse, possibly being represented by Polaris, so when a real eclipse occurred they would create as much noise as possible to scare away the dragon that was eating the Sun or Moon.Draco itself is not a very bright constellation with only three stars above magnitude 3.0 but it used to be much bigger.The Ancient Mesopotamians had actually given Draco wings which covered Ursa Major but he became a flightless dragon once they were removed in the Sixth Century.Thuban will become the pole star again in 20, 346 AD but it will most likely be less impressive than Polaris as it has an apparent magnitude of just 3.65, dim compared to Polaris’s apparent magnitude of 1.97.
Draco is not the only circumpolar constellation that can ignite our astronomical interests; the circumpolar royalty have much to offer as well.Cassiopeia the Queen and Cepheus the King are great constellations to discover, especially Cassiopeia.In mythology Cassiopeia angered Poseidon, god of the sea, by claiming her beauty surpassed that of the sea maidens!To pay for her treachery, Cassiopeia and Cepheus’s kingdom was to be ravaged by the evil sea monster Cetus, but Zeus convinced Poseidon to spare the Kingdom and instead take a sacrifice in the form of their only daughter, the beautiful Andromeda.But it has a happy ending with the Hero Perseus saving and marrying Andromeda.You can find this entire family of constellations surrounding Cassiopeia and Cepheus with many variations of the myth surrounding them.Cassiopeia resembles a ‘w’ shape in the sky and actually appears to hang upside down, which some believe to be her punishment for her vanity.But you can easily find Cassiopeia directly opposite the Plough in Ursa Major on the other side of Polaris.Cassiopeia is high in the sky during the summer months and it marks the northern most limit of the Milky Way Galaxy meaning she has many nebulae and clusters to offer both amateur and experienced stargazers.The
NGC 457 Open Cluster, Owl Cluster or as some fondly call it the ET Cluster, is one of the brightest non-Messier clusters and is quite easy to find. It is an open cluster of stars located below and right to the first V shaped in the W. It resembles a little stick figure with its arms wide open, perhaps were the ET similarities have surfaced from. To the left we have another Open Cluster M103 which is a very young, fast burning group of stars located 8,500 Light years away. This is a grouping of very hot blue stars that burn up extremely quick and at the centre the big red star was originally one of these baby blue stars but it has evolved into this giant red monster star. It is a youthful 25 million years old so it is very young indeed. These are just a few of the objects that Cassiopeia has to offer and you may find yourself wandering around the W shape finding many other enjoyable objects.
For any Moon watchers July may be a relatively quiet Month with the Full Moon over early in the month and 19 July offering us the dark New Moon.But it may increase the chances of seeing some meteors with the Delta Aquarids on the 28th and 29th radiating from the constellation of Aquarius with roughly 20 per hour to spot. Unfortunately it’s the same issue in that it’s the Southern Hemisphere that will get the best view of this shooting star delight.
As stated before, stargazing in the summer months can be quite tiring due to the limited hours of darkness but well worth it if you have the determination to fend off the land of nod.Also locally the weather has not been stargazing friendly, so if you can’t make it into those small hours or don’t wish to bombarded with tropical rainfall, come visit the planetarium and take in our new show, Beyond the Blue: A Stargazing Journey in which you will get a full view of summer sky objects and identifying skills from the comfort of our theatre seats, and all at the reasonable hour of 2pm every day seven days a week. For more details click the following link.