Constellation Monoceros (Unicorn)

Monoceros: IAU Constellation Map [150]


Monoceros is an inconspicuous constellation surrounded by conspicuous constellations like Gemini in the north, Orion in the west and Canis Maior in the south. The band of the Milky Way runs across the constellation and supplies it with a multitude of open star clusters and bright, diffuse nebulae - including the star cluster of the Rosette Nebula, which can be seen with the naked eye. The constellation area is 482 square degrees and the center culminates around midnight on January 5th. [9, 15]

Stars with Proper Names [154]
HR 2422Plaskett's Star
Data for constellation Monoceros [150]
IAU NameMonoceros
IAU GenitiveMonocerotis
IAU Abbr.Mon
English NameUnicorn
Season (47° N)October … March
Right Ascension05h 55m 52s … 08h 11m 24s
Declination-11° 22' 08" … +11° 56' 00"
Area482 deg2
Neighbours (N↻)Gem, Ori, Lep, CMa, Pup, Hya, CMi

Deep-Sky Object Descriptions



Although unicorns play an essential role in numerous legends and fables, this constellation was not yet known in ancient times. It was included in his star map by Kepler's son-in-law, the mathematician Jakob Bartsch, in 1624 after it had been used sporadically beforehand. [7] Others attribute this constellation to Johannes Hevelius, who is said to have drawn it a few decades later, in 1690. [21]

Constellation Monoceros
Constellation Monoceros: Illustration from «Prodromus Astronomiae» by Johannes Hevelius, 1690. Mirrored view from «outside of the celestial sphere» [19]
Monoceros Highlights
Monoceros Highlights: Rosetta Nebula, Christmas Tree Cluster with Cone Nebula (NGC 2264), Dreyers Nebula (IC 447) and very small Hubble's Variable Nebula (NGC 2261); Carl Zeiss Milvus Apo Sonnar T* 135 mm f/2 ZF.2 bei f/4.0; Canon EOS Ra; iOptron Skytracker Pro; 70x1 min @ 400 ASA; Muri b. Bern, 515 m AMSL; © 29. 12. 2019 Manuel Jung


  • [7] «Der grosse Kosmos-Himmelsführer» von Ian Ridpath und Wil Tirion; Kosmos Verlag; ISBN 3-440-05787-9
  • [9] «Drehbare Sternkarte SIRIUS» von H. Suter-Haug; Hallwag-Verlag, Bern
  • [15] «Hartung's Astronomical Objects for Southern Telescopes» by David Malin and David J. Frew; Melbourne University Press 1995; ISBN 0-522-84553-3
  • [19] «Prodromus Astronomiae» Johannes Hevelius, 1690; DOI:10.3931/e-rara-456
  • [21] «Taschenatlas der Sternbilder» von Josef Klepesta und Antonin Rükl; Verlag Werner Dausien; ISBN 3-7684-2384-0
  • [150] IAU: The Constellations, 11. Oktober 2020;
  • [154] Yale Bright Star Catalog, 15. Oktober 2020;