Important Summer Constellations
Summer Triangle visible from April to December
The summer triangle is overhead in summer months but is visible most of the year and can still be used as a pointer for other constellations in winter. The summer triangle connects three constellations. The tail of Cygnus the swan (Deneb – 19th brightest star), the handle in the Lyra constellation (Vega – 5th brightest star), and the tail of the eagle in the Aquila constellation (Altair – 12th brightest star). All are north of Sagittarius.
Aquila (Eagle) visible from July to October
The eagle constellation which appears as an arrow with Altair identified in the summer triangle marking its tail. The eagle is flying away from Cassiopeia and towards Scorpius. There is a second bright star along side Altair that marks the fanned tail. There are similarly bright stars equal distances marking the body and head and then 2 stars at 30 degree angles for the wings.
Cygnus (the swan or northern cross) visible from June to December
Cygnus represents a swan with a long neck and flapping wings. The swan almost perfectly dissects the summer triangle headed half way between Vega and Altair. The head of the swan is just short of the imaginary line of Vega-Altair. The midpoint of the wings span from the body just forward of perpendicular and the fully extended wings fold back at a 45 degree angle from there.
Lyra (Lyre – Ancient Harp) visible from June to October
Lyra is a small constellation with a diamond shaped instrument with a handle. Vega is the primary star that represents the handle and the diamond is dissected by the line towards Altair in the summer triangle. The full length of Lyra reaches less than half way to the head of Cygnus.
Hercules visible from March to September
Hercules is visible overhead north of Ophiuchus, alongside Lyra and near to the head of Draco. The constellation has a lack of bright stars and is a complex shape which makes it difficult to identify. However the shape is of a body builder and is therefore rewarding once identified. The head of Hercules is pointed southward and the legs stand over the head of Draco in the north sky. The brightest star in the Constellation is Kornephoros which is one of Hercules shoulders.
Because Hercules lacks bright stars it is important to first orient yourself to the correct area of sky. The easiest way is to identify the night sky immediately east of the summer triangle. Immediately east of Vega there is a quadrangle that forms the lower half of Hercules body. The square like shape is known as the keystone asterism.
From the nearest point of the square one of Hercules knees is half way back directly towards Vega. The knee is bent over 90 degrees to a star that forms a leg equal distance above and below the knee. The other leg forms from the other north facing side of the square at a 45 degree angle north-east. The upper part of the leg is slightly longer than the leg facing Vega and the bottom part of the leg is slightly shorter. The knee is bent at a 90 degree angle.
From the southern side of the quadrangle the upper half of the body broadens to the shoulders. The shape is formed with Hercules leaning slightly forward. The brightest star Kornephoros is almost in a direct line with the keystone asterism. While Sarin the other shoulder is at a 45 degree angle and nearer the quadrangle. The geometrically shaped Hercules head is marked by Ras Algethi which is equidistant from the shoulders similar to the distance of the shoulders to the body.
The arm reaching towards Vega is perpendicular to the body and is a string of stars forming a straight line. The arm extending from Kornephoros is raised and forms a slight curve of faint stars that reach a height similar to Hercules head.
This is the official formation agreed by the international astronomical union. However there is an alternate interpretation of this constellations where the keystone instead forms the head of Hercules and he is holding a club.
Summer Zodiac constellations
Virgo (Virgin) best seen in early evening sky in May
Virgo is the constellation of the Virgin and it is associated with fertility. Virgo is between Leo to the west and Libra to the east.
Libra (Scales of judgement) best seen in early evening sky in June
Libra represents the scales of judgement and is between Virgo to the west and Scorpio to the east. The constellation is a simple triangular shape with 2 weights hanging from either end. The constellation is small and lacks significant bright stars and is both difficult to find and identify its form.
Scorpio (Scorpion) best seen in early evening sky in July
Scorpio represents a Scorpion and is between Libra to the west and Ophiuchus to the east. The constellation covers a significant portion of the sky and takes an obvious form of a scorpion with a long curled stinger.
Ophiuchus (Serpent bearer) best seen in early evening sky in July
Ophiuchus represents the serpent bearer and is between Scopio to the west and Sagittarius to the east. The constellation takes an obvious form however lacks bright stars that make it difficult to identify.
Sagittarius (the Archer) best seen in early evening sky in August
Sagittarius representing the archer is between Ophiuchus to the west and Capricorn to the east. The constellation is easy to identify because of its including of the bright stars that form the teapot asterism. The shape however is less clear and most amateur star gazers prefer to simply identify the teapot.
Capricorn (Sea Goat) best seen in early evening sky in September
Capricorn represents the sea-goat and is between Sagittarius to the west and Aquarius to the east. The constellation is a simplistic triangular shape and difficult to visualise. For most viewers it is easiest to identify a roughly triangle shape for this constellation
Aquarius (the Water Bearer) best seen in early evening sky in October
Aquarius represents the water bearer and is between Capricorn to the west and Pisces to the east. The intended formation of the constellation is a man carrying a cup. However the constellation is very complex and lacks significant bright stars so is one of the most difficult to identify.
Most visible early evening constellations by month
April: Crater, Hyrda, Leo, Leo Minor, Ursa Major
May: Centaurus, Virgo
June: Libra, Lupus, Ursa Minor
July: Corona Borealis, Draco, Hercules, Ophiuchus, Scorpius
August: Aquila, Lyra, Sagittarius, Milky Way Core
September: Capricornus, Cygnus
Each of these constellations will become visible in the eastern sky before sunrise several months earlier and each day appear further west. The constellations listed are for viewing in early evening, the previous months listed constellations will appear to the immediate west. At any given time on a clear night you should be able to see at least 3 months of constellations. Additionally if you return later in the night you should see additional constellations beginning to appear, as those listed on this list will move below the horizon by midnight.