Sagittarius means an archer in Latin (from sagitta for arrow) and is represented as a centaur, half a man and half a horse with a bow and arrow. The constellation was probably created by the Babylonians, but in Greek mythology, this centaur-archer was Krotus, the son of Pan, who invented archery and lived with the Muses on Mount Helicon. For the Muses he created applause and in gratitude, the Muses asked Zeus to place him in the heavens. Sagittarius is made up of two asterisms, the teapot and the teaspoon (formerly called the milk dipper). In southern latitudes such as southern Portugal, the teapot is a striking sight, as obvious as Orion or the Plough, but sadly in Havering Sagittarius is barely visible, even with a clear southern horizon. Under Canis Major (February 2024), I remarked that 25 degrees south was about the limit for seeing things relatively easily in Havering. When one adds extinction into the mix, there are only three stars in Sagittarius which can be seen from urban southern England, Nunki (magnitude 2.1, extincted to 2.7), Kaus Borealis (2.8, extincted to 3.4) and Albaldah in the teaspoon (2.9, extincted to 3.3). The word Kaus which appears in three of the star names, comes from the Arabic for bow, hence the northern part of the bow, the middle bow and the southern bow. Nunki was a Babylonian name for Sigma Sagittarii, which was re-discovered by archaeologists and popularised by Richard Hinckley Allen.

The centre of the Milky Way lies above Alnasi and there are several star clouds in the constellation. There are numerous notable star clusters and emission nebulae as well, but they all suffer from their low latitude. I will restrict myself to deep-sky objects which lie above 25 degrees south, but even so, they are seen better by imagers than visual observers. Messier 17 [1], variously known as the Swan Nebula, the Omega Nebula and the Checkmark Nebula (among others), is an emission nebula which is a star-forming region. There is a star cluster (NGC 6618) embedded in the nebulosity. It is about 5,500 light years distant.

Moving southwards towards Polis, we find the small Sagittarius star cloud or Messier 24 [2]. This is a massive object, several times larger than the full moon, but by the same token it is difficult to make out clearly. It is very distant, perhaps about 10,000 light years. It contains the small star cluster NGC 6603, which can be seen in a telescope. Moving south-west towards the Teaspoon, we come to Messier 25 [3], a star cluster with a Cepheid variable U Sagittarii. It is about the size of the full moon and is 2,000 light years from us. Both Messier 17 and Messier 25 were discovered in 1745 by the Swiss astronomer Philippe Loys de Chéseaux and placed in his catalogue by Charles Messier in 1764.

Moving south again towards Phi Sagittarii, we reach Messier 22 [4], the Great Sagittarius Cluster, the third-brightest globular cluster in the sky and the brightest that can be seen in Havering. Unfortunately, it suffers from extinction which reduces its magnitude from 5.2 to 5.8. It is about two-thirds of the size of the full moon and lies about 11,000 light years distant. It was discovered by the German astronomer Abraham Ihle in 1665 and again, put by Messier in his catalogue, almost a century later, in 1764.

Moving to the other side of the Polis-Kaus Borealis axis, we have Messier 20 [5], better known as the Trifid Nebula, which is often reproduced as a striking astronomical image; not least in the popular American series “Lost in Space” in the 1960s and an album cover of King Crimson in 1971. Discovered by Charles Messier in 1764, it is a combination of a star cluster, an emission nebula, a reflection nebula and a dark nebula (Barnard 85). Containing thousands of young stars, it is about 4,000 light years away from us and roughly the size of the full moon.

Directly below the Trifid Nebula is the Lagoon Nebula [6] or Messier 8, which was discovered by the Italian astronomer, Giovanni Hodierna in the early 1650s and added by Messier to his catalogue in 1764. Like the Orion Nebula, it is an emission nebula which is a star nursery and contains a star cluster (NGC 6530). While it is slightly dimmer than the Orion Nebula (magnitude 4.6 vs. 4.0), the main reason why it is not more prominent in Havering is its low latitude. It is roughly three times the size of the full moon and is 4,000 light years distant.

The dwarf planet Ceres is currently moving across Sagittarius. In mid-July 2024 it will be roughly at position a and will be magnitude 7.5 (reduced to 8.4 by extinction).