IAU designated constellations by area

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Hydra is the largest constellation, covering more than
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1/32 of the night sky and 19 times the area of Crux, the smallest constellation. Hydra constellation map.svg
Hydra is the largest constellation, covering more than 132 of the night sky and 19 times the area of Crux, the smallest constellation.

The International Astronomical Union (IAU) designates 88 constellations of stars. In the table below, they are ranked by the solid angle that they subtend in the sky, measured in square degrees and millisteradians.

These solid angles depend on arbitrary boundaries between the constellations: the list below is based on constellation boundaries drawn up by Eugène Delporte in 1930 on behalf of the IAU and published in Délimitation scientifique des constellations (Cambridge University Press). Before Delporte's work, there was no standard list of the boundaries of each constellation.

Delporte drew the boundaries along vertical and horizontal lines of right ascension and declination; however, he did so for the epoch B1875.0, which means that due to precession of the equinoxes, the borders on a modern star map (e.g., for epoch J2000) are already somewhat skewed and no longer perfectly vertical or horizontal. This skew will increase over the centuries to come. However, this does not change the solid angle of any constellation.

RankAbbrev. Constellation Solid angle
("Area")
(sq. deg.) [1]
Solid angle
(millisteradians)
Per­cent­age Right ascension
(hours & mins) [2]
Decli­nation
(degs & mins) [3]
Quad [4]
01Hya Hydra 1302.844396.8693.16%+11 36.73−14 31.91SQ2
02Vir Virgo 1294.428394.3053.14%+13 24.39−04 09.51SQ3
03UMa Ursa Major 1279.660389.8073.10%+11 18.76+50 43.27NQ2
04Cet Cetus 1231.411375.1092.99%+01 40.10−07 10.76SQ1
05Her Hercules 1225.148373.2012.97%+17 23.16+27 29.93NQ3
06Eri Eridanus 1137.919346.6302.76%+03 18.02−28 45.37SQ1
07Peg Pegasus 1120.794341.4132.72%+22 41.84+19 27.98NQ4
08Dra Draco 1082.952329.8862.63%+15 08.64+67 00.40NQ3
09Cen Centaurus 1060.422323.0232.57%+13 04.27−47 20.72SQ3
10Aqr Aquarius 979.854298.4812.38%+22 17.38−10 47.35SQ4
11Oph Ophiuchus 948.340288.8812.30%+17 23.69−07 54.74SQ3
12Leo Leo 946.964288.4622.30%+10 40.03+13 08.32NQ2
13Boo Boötes 906.831276.2372.20%+14 42.64+31 12.16NQ3
14Psc Pisces 889.417270.9322.16%+00 28.97+13 41.23NQ1
15Sgr Sagittarius 867.432264.2352.10%+19 05.94−28 28.61SQ4
16Cyg Cygnus 803.983244.9071.95%+20 35.28+44 32.70NQ4
17Tau Taurus 797.249242.8561.93%+04 42.13+14 52.63NQ1
18Cam Camelopardalis 756.828230.5431.83%+08 51.37+69 22.89NQ2
19And Andromeda 722.278220.0181.75%+00 48.46+37 25.91NQ1
20Pup Puppis 673.434205.1401.63%+07 15.48−31 10.64SQ2
21Aur Auriga 657.438200.2671.59%+06 04.42+42 01.68NQ2
22Aql Aquila 652.473198.7551.58%+19 40.02+03 24.65NQ4
23Ser Serpens [5] 636.928194.0191.54%+16 57.04+06 07.32NQ3
24Per Perseus 614.997187.3391.49%+03 10.50+45 00.79NQ1
25Cas Cassiopeia 598.407182.2851.45%+01 19.16+62 11.04NQ1
26Ori Orion 594.120180.9791.44%+05 34.59+05 56.94NQ1
27Cep Cepheus 587.787179.0501.42%+02 32.64+71 00.51NQ4
28Lyn Lynx 545.386166.1341.32%+07 59.53+47 28.00NQ2
29Lib Libra 538.052163.9001.30%+15 11.96−15 14.08SQ3
30Gem Gemini 513.761156.5011.25%+07 04.24+22 36.01NQ2
31Cnc Cancer 505.872154.0971.23%+08 38.96+19 48.35NQ2
32Vel Vela 499.649152.2021.21%+09 34.64−47 10.03SQ2
33Sco Scorpius 496.783151.3291.20%+16 53.24−27 01.89SQ3
34Car Carina 494.184150.5371.20%+08 41.70−63 13.16SQ2
35Mon Monoceros 481.569146.6941.17%+07 03.63+00 16.93NQ2
36Scl Sculptor 474.764144.6211.15%+00 26.28−32 05.30SQ1
37Phe Phoenix 469.319142.9631.14%+00 55.91−48 34.84SQ1
38CVn Canes Venatici 465.194141.7061.13%+13 06.96+40 06.11NQ3
39Ari Aries 441.395134.4571.07%+02 38.16+20 47.54NQ1
40Cap Capricornus 413.947126.0951.00%+21 02.93−18 01.39SQ4
41For Fornax 397.502121.0860.96%+02 47.88−31 38.07SQ1
42Com Coma Berenices 386.475117.7270.94%+12 47.27+23 18.34NQ3
43CMa Canis Major 380.118115.7910.92%+06 49.74−22 08.42SQ2
44Pav Pavo 377.666115.0440.92%+19 36.71−65 46.89SQ4
45Gru Grus 365.513111.3420.89%+22 27.39−46 21.11SQ4
46Lup Lupus 333.683101.6460.81%+15 13.21−42 42.53SQ3
47Sex Sextans 313.51595.5020.76%+10 16.29−02 36.88SQ2
48Tuc Tucana 294.55789.7270.71%+23 46.64−65 49.80SQ4
49Ind Indus 294.00689.5590.71%+21 58.33−59 42.40SQ4
50Oct Octans 291.04588.6570.71%+23 00.00−82 09.12SQ4
51Lep Lepus 290.29188.4280.70%+05 33.95−19 02.78SQ1
52Lyr Lyra 286.47687.2660.69%+18 51.17+36 41.36NQ4
53Crt Crater 282.39886.0230.68%+11 23.75−15 55.74SQ2
54Col Columba 270.18482.3030.65%+05 51.76−35 05.67SQ1
55Vul Vulpecula 268.16581.6880.65%+20 13.88+24 26.56NQ4
56UMi Ursa Minor 255.86477.9410.62%+15 00.00+77 41.99NQ3
57Tel Telescopium 251.51276.6150.61%+19 19.54−51 02.21SQ4
58Hor Horologium 248.88575.8150.60%+03 16.56−53 20.18SQ1
59Pic Pictor 246.73975.1610.60%+05 42.46−53 28.45SQ1
60PsA Piscis Austrinus 245.37574.7450.59%+22 17.07−30 38.53SQ4
61Hyi Hydrus 243.03574.0330.59%+02 20.65−69 57.39SQ1
62Ant Antlia 238.90172.7730.58%+10 16.43−32 29.01SQ2
63Ara Ara 237.05772.2120.57%+17 22.49−56 35.30SQ3
64LMi Leo Minor 231.95670.6580.56%+10 14.72+32 08.08NQ2
65Pyx Pyxis 220.83367.2700.54%+08 57.16−27 21.10SQ2
66Mic Microscopium 209.51363.8210.51%+20 57.88−36 16.49SQ4
67Aps Apus 206.32762.8510.50%+16 08.65−75 18.00SQ3
68Lac Lacerta 200.68861.1330.49%+22 27.68+46 02.51NQ4
69Del Delphinus 188.54957.4350.46%+20 41.61+11 40.26NQ4
70Crv Corvus 183.80155.9890.45%+12 26.52−18 26.20SQ3
71CMi Canis Minor 183.36755.8570.44%+07 39.17+06 25.63NQ2
72Dor Dorado 179.17354.5790.43%+05 14.51−59 23.22SQ1
73CrB Corona Borealis 178.71054.4380.43%+15 50.59+32 37.49NQ3
74Nor Norma 165.29050.3500.40%+15 54.18−51 21.09SQ3
75Men Mensa 153.48446.7540.37%+05 24.90−77 30.24SQ1
76Vol Volans 141.35443.0590.34%+07 47.73−69 48.07SQ2
77Mus Musca 138.35542.1450.34%+12 35.28−70 09.66SQ3
78Tri Triangulum 131.84740.1630.32%+02 11.07+31 28.56NQ1
79Cha Chamaeleon 131.59240.0850.32%+10 41.53−79 12.30SQ2
80CrA Corona Australis 127.69638.8980.31%+18 38.79−41 08.85SQ4
81Cae Caelum 124.86538.0360.30%+04 42.27−37 52.90SQ1
82Ret Reticulum 113.93634.7070.28%+03 55.27−59 59.85SQ1
83TrA Triangulum Australe 109.97833.5010.27%+16 04.95−65 23.28SQ3
84Sct Scutum 109.11433.2380.26%+18 40.39−09 53.32SQ4
85Cir Circinus 93.35328.4370.23%+14 34.54−63 01.82SQ3
86Sge Sagitta 79.93224.3490.19%+19 39.05+18 51.68NQ4
87Equ Equuleus 71.64121.8230.17%+21 11.26+07 45.49NQ4
88Cru Crux 68.44720.8500.17%+12 26.99−60 11.19SQ3
Notes
  1. The total solid angle of all constellations is the total solid angle of the sky, which is exactly 4π steradians, or 4π × (180/π)2 = 129,600/π square degrees, or approximately 41,252.961 square degrees. The figures in the table do not sum precisely to this number due to rounding errors, which vanish when the areas are rounded instead to one decimal place.
  2. Average of the most eastward and most westward RA.
  3. Average of the most northern and most southern declination.
  4. "Quad" designates the quadrant of the sky as N for North or S for South, Quadrants 1 (0h6h), 2 (6h12h), 3 (12h18h), or 4 (18h0h).
  5. Serpens is divided into two parts:
    Serpens Caput ("Serpent's Head"; 428.484 sq. deg.; midpoint: RA: 15 46.49, Dec: +10 58.20), and
    Serpens Cauda ("Serpent's Tail"; 208.444 sq. deg.; midpoint: RA: 18 07.60, Dec: -04 51.73)

See also

Sources

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