Smallest Constellations

The smallest constellations in the sky are Crux, Equuleus, Sagitta, Circinus and Scutum. The smallest northern constellations are Equuleus, Sagitta, Triangulum, Corona Borealis and Canis Minor, and the southern ones are Crux, Circinus, Scutum, Triangulum Australe and Reticulum.

The smallest southern constellations, image: Wikisky

While many of the smallest constellations are also among the faintest and least distinct, this is not the case with all of them. Crux, the Southern Cross, is one of the best known constellations in the sky. It is used in navigation to find true north and its bright stars are featured on the flags of several countries and territories. Three of the constellation’s five brightest stars are among the 25 brightest stars in the sky. However, while the constellation is one of the most familiar patterns to observers in the southern hemisphere, it is invisible to northern observers living north of latitude 20°N.

North of the celestial equator, the constellations Corona Borealis, Triangulum and Canis Minor are relatively easy to spot on a clear night. Corona Borealis has a distinctive semi-circular asterism representing the Northern Crown that makes it easy to find between the larger Hercules and Boötes. Triangulum‘s long narrow triangle is easy to locate between the bright stars of Andromeda and Aries constellations. Canis Minor is easily identified because it is home to Procyon, one of the brightest stars in the sky and one of the vertices of the Winter Hexagon and Winter Triangle asterisms.

The smallest northern constellations, image: Wikisky

Equuleus and Sagitta, the 2nd and 3rd smallest constellations, lie in the same area of the northern sky and are separated by Delphinus, another small constellation with a distinctive shape. All three are Greek constellations, listed by Ptolemy in his Almagest. While Equuleus is quite faint and indistinct, Sagitta can be identified in good conditions. Its shape resembles that of an arrow and it can be found between the two large northern birds: Cygnus and Aquila.

Many of the smallest constellations in the sky are those introduced by the German uranographer Johann Bayer in the early 17th century and French astronomer Nicolas-Louis de Lacaille in the 18th century. These constellations are located in the southern celestial hemisphere and due to their position far south they remained unknown to northern observers until the Age of Discovery.

Most of these constellations are named after instruments (Circinus, Reticulum, Caelum) or exotic animals (Chamaeleon, Volans, Dorado).  Those introduced by Bayer were created by the Dutch-Flemish cartographer Petrus Plancius based on observations of Dutch explorers and are named after various animals they encountered on their journeys. The constellations created by Lacaille, on the other hand, represent various scientific instruments.  As many of these constellations are invisible to northern observers living north of tropical latitudes, they are still largely unknown in the northern hemisphere.

Below is the list of the 88 modern constellations ordered by size, from smallest to largest.

Constellation Size (area in square degrees) Quadrant
1.       Crux 68.447 SQ3
2.       Equuleus 71.641 NQ4
3.       Sagitta 79.932 NQ4
4.       Circinus 93.353 SQ3
5.       Scutum 109.114 SQ4
6.       Triangulum Australe 109.978 SQ3
7.       Reticulum 113.936 SQ1
8.       Caelum 124.865 SQ1
9.       Corona Australis 127.696 SQ4
10.   Chamaeleon 131.592 SQ2
11.   Triangulum 131.847 NQ1
12.   Musca 138.355 SQ3
13.   Volans 141.354 SQ2
14.   Mensa 153.484 SQ1
15.   Norma 165.290 SQ3
16.   Corona Borealis 178.710 NQ3
17.   Dorado 179.173 SQ1
18.   Canis Minor 183.367 NQ2
19.   Corvus 183.801 SQ3
20.   Delphinus 188.549 NQ4
21.   Lacerta 200.688 NQ4
22.   Apus 206.327 SQ3
23.   Microscopium 209.513 SQ4
24.   Pyxis 220.833 SQ2
25.   Leo Minor 231.956 NQ2
26.   Ara 237.057 SQ3
27.   Antlia 238.901 SQ2
28.   Hydrus 243.035 SQ1
29.   Piscis Austrinus 245.375 SQ4
30.   Pictor 246.739 SQ1
31.   Horologium 248.885 SQ1
32.   Telescopium 251.512 SQ4
33.   Ursa Minor 255.864 NQ3
34.   Vulpecula 268.165 NQ4
35.   Columba 270.184 SQ1
36.   Crater 282.398 SQ2
37.   Lyra 286.476 NQ4
38.   Lepus 290.291 SQ1
39.   Octans 291.045 SQ4
40.   Indus 294.006 SQ4
41.   Tucana 294.557 SQ4
42.   Sextans 313.515 SQ2
43.   Lupus 333.683 SQ3
44.   Grus 365.513 SQ4
45.   Pavo 377.666 SQ4
46.   Canis Major 380.118 SQ2
47.   Coma Berenices 386.475 NQ3
48.   Fornax 397.502 SQ1
49.   Capricornus 413.947 SQ4
50.   Aries 441.395 NQ1
51.   Canes Venatici 465.194 NQ3
52.   Phoenix 469.319 SQ1
53.   Sculptor 474.764 SQ1
54.   Monoceros 481.569 NQ2
55.   Carina 494.184 SQ2
56.   Scorpius 496.783 SQ3
57.   Vela 499.649 SQ2
58.   Cancer 505.872 NQ2
59.   Gemini 513.761 NQ2
60.   Libra 538.052 SQ3
61.   Lynx 545.386 NQ2
62.   Cepheus 587.787 NQ4
63.   Orion 594.120 NQ1
64.   Cassiopeia 598.407 NQ1
65.   Perseus 614.997 NQ1
66.   Serpens 636.928 NQ3
67.   Aquila 652.473 NQ4
68.   Auriga 657.438 NQ2
69.   Puppis 673.434 SQ2
70.   Andromeda 722.278 NQ1
71.   Camelopardalis 756.828 NQ2
72.   Taurus 797.249 NQ1
73.   Cygnus 803.983 NQ4
74.   Sagittarius 867.432 SQ4
75.   Pisces 889.417 NQ1
76.   Boötes 906.831 NQ3
77.   Leo 946.964 NQ2
78.   Ophiuchus 948.340 SQ3
79.   Aquarius 979.854 SQ4
80.   Centaurus 1060.422 SQ3
81.   Draco 1082.952 NQ3
82.   Pegasus 1120.794 NQ4
83.   Eridanus 1137.919 SQ1
84.   Hercules 1225.148 NQ3
85.   Cetus 1231.411 SQ1
86.   Ursa Major 1279.660 NQ2
87.   Virgo 1294.428 SQ3
88.   Hydra 1302.844 SQ2