Sagittarius Constellation

If you’re learning about constellations, then one that you’ve likely already heard of is Sagittarius. This archer constellation has many different stars in it, which make it one of the larger of the 88 constellations. Lets look at some facts about Sagittarius.

  • Bordered By; Aquila, Scutum, Serpens Cauda, Ophiuchus, Scorpius, Corona Australis, Telescopium, Indus, Microscopium, Capricornus.
  • Named after; The Archer
  • Declination; -25°
  • Brightest Star; Kaus Australis 
  • Best seen; July-August
  • Size rank; 15th
  • Constellation family; Zodiac
  • Pronunciation; SAJ-JIT-AIR-REE-US

What is Sagittarius named after?

In Babylonian mythology, Sagittarius was a centaur with a human head. This is the same as in Greek mythology, where centaurs are half man and half horse. It’s said that this centaur was riding into battle, which is why it has a bow ready to fire like an archer. Of course, there is actually another centaur constellation, called Centaurus.

Who founded the Sagittarius Constellation?

The first writings that we have of the constellation Sagittarius come from Greek astronomer Ptolemy. Ptolemy was thought to have built his knowledge based on previous dynasties, like the Egyptians and the Babylonians. So, it is likely that Ptolemy just marked this constellation down as something that he himself had been taught.

How can I see Sagittarius in the sky?

If you’re in the Northern hemisphere, then the best time to see Sagittarius is throughout the summer (July-September). However, Sagittarius is best seen from the Southern hemisphere throughout other times of the year.

Main Stars of Sagittarius

There are many different stars in the constellation Sagittarius. Let’s look at some of the main ones, where you can match them up with their name below.

  • Rukbat (α)- The most well known star in the Sagittarius constellation is known as Rukbat, or Alpha Sagittarii. It is a blue dwarf star, with a luminosity greater than 117x that of the Sun.
  • Arkab Prior (β1) – Beta Sagittarii, also known as Arkab Prior, is within close proximity of Rukbat. It is a binary star system, made up of a primary b type main sequence star that is around 224 million years old.
  • Arkab Posterior (β²) – Beta² Sagittarii, is also known as Arkab Posterior, is another binary star system, with the primary being an F-type giant star. It’s estimated to be much older than β1, with an estimated of around 930 million years.
  • Ascella (ζ) – Ascella is also known as Zeta Sagittarii, and it is the third brightest star in this constellation. It is comprised of a triple star system.
  • Kaus Borealis (λ) – Lambda Sagittarii, which we refer to as Kaus Borealis, is a giant star that has a radius that is 11x that of our Sun. This star makes up the top of the bow that the Archer is using.
  • Alnasl (γ²) – Alnasl is the common name for the star Gamma² Sagittarii. It is the tip of the arrow, and is the 7th brightest star in this constellation.
  • Kaus Media (δ) – Delta Sagittarii, or Kaus Media, is around 348 light years away from the Sun. It is bright enough that it is easily visible without a telescope.
  • Kaus Australis (ε) – Epsilon Sagittarii, also referred to as Kaus Australis, is a binary star system which is the brightest in this constellation.
  • Nunki (σ) – Sigma Sagittarii , which is commonly referred to as Nunki, is the 2nd brightest star in Sagittarius. It has a distance of 228 light years from the Sun.


In conclusion, Sagittarius is one of the most well known constellations due to it’s Zodiac family. It has many stars, although they aren’t as bright as stars in other constellations. Although it is bright during the summer for much of Europe, it’s actually not even visible in some Northern countries like Scotland.