Sagittarius Constellation

The Sagittarius constellation of the ‘centaur archer’ represents the Zodiac month from November 23 – December 21. However, in modern times the sun passes through the Sagittarius constellation approximately 1 month later. The Sagittarius constellation is near to the core of the milky way and therefore a popular constellation. The full form of the constellation is difficult to interpret but the teapot asterism at its centre is one of the easiest formations to find. The constellation is between Scorpius and Ophiuchus to the west and Capricornus to the east. The teapot of Sagittarius is a popular summer asterism to identify and it made easy to find with its location at the core of the Milky Way. Although it is low in the southern sky at high northern hemisphere latitudes it is prominent from locations below 30 degrees northern latitude. Because of its location it is only visible for a short part of the year for northern hemisphere viewers.

The Sagittarius constellation is one of the original 48 constellations listed by the Egyptian mathematician Ptolemy, who lived under Roman rule in Alexandria in the 2nd century. These constellations formed the basis for the modern list agreed by the IAU. Constellations from the southern hemisphere, unable to be seen from the Mediterranean, represent the majority of additions to the list.

As the earth moves in its orbit around the sun, each night you are looking at a different portion of the sky. When looking at stars it is important to be aware of what is within your view. Northern hemisphere stargazers can group constellations into 3 groups; circumpolar, summer and winter constellations. The circumpolar constellations are in the north sky, appear to move around the north star and are visible throughout the year. The constellations in the south sky are only visible for part of the year and are grouped as either summer or winter constellations. Each is visible from between 4 to 10 months.

It is important to be aware of the specific time of year and hour of the night when deciding what to look for. These pages below show the constellations in each group so you can find the constellations that interest you. 

CIRCUMPOLAR (year around) – Ursa Major – Cassiopeia – Ursa Minor – Draco – Cepheus

WINTER – Pegasus – Pisces – Aries – Auriga – Taurus – Orion – Canis Major  – Canis Minor – Gemini – Lynx – Cancer – Leo – Winter Hexagon

SUMMER – Virgo – Libra – Scorpius – Bootes – Hercules – Lyra – Ophiuchus – Sagittarius – Aquila – Cygnus – Capricornus – Aquarius

Or use this guide to easily see which constellations are easiest to find right now:

BEST CONSTELLATIONS TO FIND THIS MONTH

Sagittarius Quick Facts:

Symbolism: Archer or Centaur with a bow

Neighbouring constellations: Scorpius (south west), Ophiuchus (north west), Capricornus (east), Aquila (north)

Brightest star: Kaus Australis, +1.84 magnitude (37th brightest star in the night sky)

Stars brighter than 3 magnitude: 7

Primary stars: 8 (Primary shape of the constellation is the teapot asterism – 4 stars for the handle, 3 stars for the spout and 1 star for the lid)

Latitude: 20 – 35 degrees south

Northern Hemisphere Season: Summer (March – October)

Which months can you see Sagittarius constellation?

Sagittarius constellation can be seen from January to November but can be found high in the sky at 21:00 during the month of August:

• Early evening viewers (before 21:00) can find the constellation from July in the eastern sky until November in the western sky. Sagittarius constellation will be visible overhead in September.
• Mid evening viewers (21:00-23:30) can find the constellation from June in the eastern sky until September in the western sky. Sagittarius constellation will be visible overhead in August.
• Late evening viewers (after 23:30) can find the constellation from May in the eastern sky until August in the western sky. Sagittarius will be visible overhead in July.
• Early morning viewers can find the constellation from January in the eastern sky to June in the western sky. Sagittarius will be visible overhead in April-May.

As time passes the constellation will gradually appear earlier in the night with ranges below showing the window of opportunity in each month. Sagittarius constellation sits between 20 – 35 degrees south latitude. Therefore, the further south your position the further north it will appear in the sky. At its maximum range it is possible to see Sagittarius at latitudes between +55 and -90.

Best time to see Sagittarius constellation:

Best visible at 21:00 in August

February: breifly visible on the south east horizon before sunrise from 04:30.

March: appear on the south east horizon at 02:30. It will reach 25 degrees above the south east horizon by sunrise.

April: appear on the south east horizon at 02:00. It will reach 30 degrees above the southern horizon by sunrise.

May: appear on the south east horizon at 00:30, reaching its peak 30 degrees above the southern horizon at 04:00. It will continue moving west until sunrise when it will be 30 degrees above the southern horizon.

June: appear on the south east horizon at 22:30, reaching its peak 30 degrees above the southern horizon at 02:00. It will continue moving west until sunrise when it will be 20 degrees above the southern horizon.

July: appear on the south east horizon at 20:30, reaching its peak 30 degrees above the southern horizon at 00:00. It will continue moving west until 03:30 when it will begin to be only partially visible on the south west horizon.

August: 25 degrees above the south east horizon at sunset, reaching its peak 30 degrees above the southern horizon at 22:00. It will continue moving west until 01:30 when it will begin to be only partially visible on the south west horizon.

September: 30 degrees above the southern horizon at sunset, reaching its peak 30 degrees above the southern horizon at 20:00. It will continue moving west until 23:30 when it will begin to be only partially visible on the south west horizon.

October: 30 degrees above the southern horizon at sunset. It will continue moving west until 20:30 when it will begin to be only partially visible on the south west horizon.

November: 20 degrees above the south west horizon at sunset. It will continue moving west until 19:30 when it will begin to be only partially visible on the south west horizon.

Trajectory: The constellation is between 20 – 35 degrees south which means that for those in low latitudes of the northern hemisphere is will pass in the southern sky. For those in higher latitudes of the northern hemisphere it will appear very low in the southern sky for limited time each night. Its peak trajectory in Wadi Rum is 30 degrees above the southern horizon from April through September.

Not the right time for Sagittarius constellation? Have a look what constellations you can see tonight.

How to find Sagittarius constellation?

Difficulty to find: Medium – Difficulty to interpret: Hard – Locating asterism: Milky Way

Sagittarius is popular as it is the reference for locating the core of the milky way. The milky way core is often referenced as the steam rising from the teapot spout at the centre of the Sagittarius constellation.

The most useful aide in finding Sagittarius is the Milky Way. The Milky Way is prominent in the sky and Sagittarius is at its core. The other two bright formations adjacent to Sagittarius that can be used are the Summer triangle (which covers the constellations of Aquila, Cygnus and Lyra) or Scorpius.

For viewers in the northern hemisphere it passes low across the southern sky. Therefore it is only present in the sky for a shorter duration of the night.

Option 1: Core of the milky way

The core of the milky way is the brightest most concentrated area of light. Alnasl the star at the tip of the spout appears within the core of the milky way. When the milky way is present in night sky it is prominent and forms a long streak of bright light across the sky. The brightest part of this is the core and can be used as a reference point to trace the shape of Sagittarius 

Option 2: Summer Triangle

The summer triangle which is a prominent asterism in the night sky throughout summer for northern hemisphere viewers. It is useful to be familiar with and helps locate many constellations throughout summer. The triangle links the 3 bright stars of Altair, Deneb and Vega in the constellations of Aquila, Cygnus, Lyra respectively.

The constellation of Aquila which forms the shape of an Eagle points directly at Sagittarius. Move away from the Altair and move between one and two lengths of the eagle to find Sagittarius. If you follow the Triangle as it points south you will move slightly west of Sagittarius and can use this to help in identifying its location.

Option 3: Scorpius

For viewers familiar with Scorpius and trying to locate Sagittarius immediately after it has risen can use the tail of Scorpius. The stinger at the end of the tail of the scorpion is very near to Sagittarius and points at the base of the teapot. If you follow the curve of the tail it will lead y0u directly to the teapot. Follow beyond the stinger double its length to find the star at the base of the teapot  nearest its spout.

Learn how to form the shape of Sagittarius constellation

The primary shape of Sagittarius is the well known teapot asterism. The handle of the teapot points north west and the spout of the teapot faces south east.

Beginning from the tip of the spout which is located in the core of the milky way.

• At the edge of the core is the star that represents where the spout connects to the body of the teapot.
• Following north along the edge of the core is the top of the teapot around double the distance from the top corner as the spout. To locate this star turn right around 45 degrees when following the top of the spout.
• From the top of the teapot turn left 90 degrees and move slightly less distance to find the other upper corner, nearest to the handle.
• The brightest star in the constellation is at the base of the teapot nearest to the spout. It is southwest of the spout around the distance of the bright core away from the tip of the spout.
• The star at the base closest to the handle can  be found by following a line parallel to the stars in the top corners. The base of the pot is double the length of the base of the spout.
• The lower star in the handle is around a quarter the distance of the base of the teapot.
• The upper star in the handle can be found by turning 90 degrees right and travelling around double the distance.

These 8 stars form the prominent teapot asterism and are the main formation within Sagittarius.

Finding the centaur shape imagined by ancient astronomers and explorers:

From the names of the stars and the depictions in ancient texts it can be determined that the bow was formed by the front of the teapot. References to the arrow of Sagittarius aiming for the heart of Scorpius indicates that the spout of the teapot is the arrow.

The handle is said to represent the arm of the centaur tensioning the bow concluded from star names. This gives the viewer a good understanding of the formation initially.

• The point at the top and the two stars at the front of the pot at the bow.
• With the tip of the spout is the arrow.
• The handle represents the bent arm tensioning the bow.

There is a string of less bright stars to the south west of the teapot that represent the body and legs of the centaur with stars named as the legs. There are additional bright stars north west of the teapot and in most ancient depictions Sagittarius has a cape. Although in some images these are shown to represent arrows on his back.

Sagittarius constellation in the Ancient World

Ancient Babylon

Sagittarius was modelled from the Babylonian god Nergal. He was depicted with 2 heads, wings and and the body of different animals. Nergal is attributed as being the sun god in earliest records. Nergal is depicted shooting a flaming arrow and closely related to both the midday sun and fire.

The old testament makes reference to Nergal in 2 Kings 17:30. Many of his attributes were carried to the Persian sun god. Sumerian texts referenced the constellation as the chief ancestor which aligns with many sun dieties who are represented as the god or origin and leader of the gods. Later Nergal became more associated with the war and the underworld and in Greek mythology was associated more with the god of war Ares.

Greek mythology

In Greek mythology Sagittarius is associated with the centaur. A half horse, half human creature that was common in Greek myths. Sagittarius is said to represent Chiron, the centaur tasked with protecting and training Jason of the Argonauts. Jason is a prominent figure in Greek mythology for his quest for the golden fleece. Other students of Chiron include Hercules, Archilles and Theseus. Chiron transformed into a centaur to hide from his wife. There are 2 centaurs among the constellations recorded by Ptolemy and Chiron is said to have entered the sky to hide alongside the other centaur already among the stars.

An alternative explanation is that Chiron is represented by the Centaurus constellation and Sagittarius represents Crotus. Crotus was a centaur that the ancient Greeks attributed with the invention of archery. This explains why Sagittarius is always depicted as an archer. 

Main stars in Sagittarius constellation

Kaus Australis (+1.84m, 143ly, double star, #37)

Kaus is from the Arabic for ‘bow’ and Australis is from the Latin for ‘southern’. It is the 37th brightest star with an apparent magnitude of +1.84. The distance from earth is 143 light years. It is a double star system with the primary star more than 300 times the size of the sun. Kaus Australis marks the base of the spout of the teapot.

Nunki (+2.05m, 228ly, triple star, #52)

Nunki is a word of Assyrian or Babylonian origin with unknown meaning. It is the 52nd brightest star with an apparent magnitude of +2.05. The distance from earth is 228 light years. It is around 90 times the size of the sun. Nunki marks the tip of the upper part of the curve of the handle of the teapot.

Ascella (+2.60m, 88ly, triple star, #101)

Ascella is from Latin meaning ‘armpit’. It is the 101st brightest star with an apparent magnitude of +2.60. The distance from earth is 88 light years. It is a triple star system. Ascella marks the where the handle joins the base of the teapot.

Kaus Media (+2.72m, 348ly, double star,  #117)

Kaus is from the Arabic for ‘bow’ and Media is from the Latin for ‘middle’. It is the 117th brightest star with an apparent magnitude of +2.72. The distance from earth is 348 light years. It is a double star system with the primary star around 4000 times the size of the sun. Kaus Media marks the where the spout connects to the top of the teapot.

Kaus Borealis (+2.82m, 78ly, 1.4k suns, #136)

Kaus is from the Arabic for ‘bow’ and Borealis is from the Latin for ‘north’. It is the 136th brightest star with an apparent magnitude of +2.82. The distance from earth is 78 light years. It is around 1400 times the size of the sun. Kaus Borealis marks the lid of the teapot

Albaldah (+2.88m, 510ly, triple star, #152)

Albaldah is from Arabic meaning ‘the town’. It is the 152nd brightest star with an apparent magnitude of +2.88. The distance from earth is 510 light years. Although it appears as a single source of light, it is a triple star system. Albaldah is north east of the teapot.

Alnasl (+2.98m, 97ly, 1700 suns,#168)

Alnasl is from the Arabic for ‘arrow head’. It is the q68th brightest star with an apparent magnitude of +2.98. The distance from earth is 97 light years. It is around1700 times the size of the sun. Alnasl marks the tip of the spout of the teapot.

Deep Sky Objects

Large Sagittarius Star Cloud – At the bright innermost core of the milky way, a large star cloud with a group of stars and star clusters.

Small Sagittarius Star Cloud – A secondary bright formation with a heavy concentration of stars allowing over 100o stars to be seen through binoculars.

Lagoon Cluster – A cluster with a pink hue that has a central component known as the hourglass cluster for its unique shape.

Omega Nebula – Also known as the horseshoe nebula or swan nebula.

Trifid Nebula – Nebula with a blue outer ring and pink interior with a triple star system at its core.

Red Spider Nebula – an X shaped Nebula with a single dominant star at its core.

Wadi Rum is one of the best locations in the world to see the full beauty of the stars. Combining high altitudes, clear skies and no light pollution. You may be surprised how many stars are visible to the naked eye. Come with us and spend a night under the stars.