Corona Borealis

Corona Borealis (Latin for northern crown) is a small northern constellation whose main stars form a semicircular arc. It is one of the 88 modern constellations, and was also one of the 48 constellations listed by Ptolemy, who referred to the constellation as Corona. The Borealis (northern) was added later on, to contrast with Corona Australis, the southern crown.

Corona borealis

Constellation
Corona borealis List of stars in Corona borealis
Abbreviation	CrB
Genitive	Coronae Borealis
Right ascension	16
Declination	+30
Area	179 sq. deg. (73rd)
Meteor showers	None
Bordering constellations	Hercules Boötes Serpens Caput
Visible at latitudes between +90° and −50°. Best visible at 21:00 (9 p.m.) during the month of July.

Notable features

It has no first magnitude stars. Its brightest star, α CrB (Alphecca, also known as Gemma) is of magnitude 2.2 (slightly variable) and is considered a member of the diffuse Ursa Major Moving Group. The constellation contains several interesting variable stars: two of the best known are R Coronae Borealis and T Coronae Borealis.

Notable deep sky objects

Corona Borealis contains no bright deep sky objects. Abell 2065 is a a highly concentrated galaxy cluster containing over 400 members, the brightest of which are of 16th magnitude.

Mythology

Corona Borealis was sometimes considered to represent a crown that was given by Dionysus to Ariadne, the daughter of Minos of Crete. At other points it was considered to belong, in a sense, to Boötes, whomever that might represent.

Stars

Stars with proper names:

• (5/α CrB) 2.22 Alphecca [Alphacca, Alphekka] or Gemma or Gnosia [Gnosia Stella Coronae] or Asteroth [Ashtaroth]

  < النائر الفكّة an-na´ir al-fakkah The bright one of the broken (ring of stars)

  < gemma The jewel

  < gnōsia stella corōnæ Star of Ariadne's ("of Knossos's") crown

  < עשתרזת ^cašterôt, Astarte (idols) [plural of Ashtoreth Astarte/Ishtar, the Semitic fertility goddess]

• (3/β CrB) 3.66 Nusakan

  < ? an-nasaqan The (two) series

Stars with Bayer designations:

8/γ CrB 3.81; 10/δ CrB 4.59; 13/ε CrB 4.14; 7/ζ¹ CrB 6.00; 7/ζ² CrB 5.07; 4/θ CrB 4.14; 2/η CrB – double 4.99, 6.08; 14/ι CrB 4.98; 11/κ CrB 4.79; 12/λ CrB 5.43; 6/μ CrB 5.14; 20/ν¹ CrB 5.20; 21/ν² CrB 5.40; 19/ξ CrB 4.86; 1/ο CrB 5.51; 9/π CrB 5.57; 15/ρ CrB 5.39 – has a planet; 17/σ CrB – double 5.23, 6.66; 16/τ CrB 4.73; 18/υ CrB 5.80

Other notable stars:

• R CrB 5.85 - 14.8 – R CrB variable prototype

External links

• The Deep Photographic Guide to the Constellations: Corona Borealis