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Nu Coronae Borealis — Star in Corona Borealis

HIP 80197; Nu Coronae Borealis; 20 Coronae Borealis

Magnitude 5.2m Star Corona Borealis (CrB) Visible
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Observe

1Physical Properties

Magnitude 5.20
Spectral Type M2IIIab bright giant
Star Color Red (B-V 1.60)
Distance 1,087 ly

2Position & Identifiers

RA 16h 22m 21.4s
Dec +33° 47' 57.0"
Constellation Corona Borealis (CrB)
HR 6107
HIP 80197
HD 147749
SAO 65257
Bayer Nu
Flamsteed 20 CrB
SIMBAD Wikipedia

3How easy to spot?

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Equipment Bortle 3 Bortle 4 Bortle 5
Naked eye Medium Hard+ Hard
50mm finder Easy Easy Easy
150mm scope Easy Easy Easy
Easy Medium Hard Very hard Impossible

Bortle 3 = rural · 4 = outer suburbs · 5 = suburbs

4Visibility

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Best season Apr – Jun (peak: May)

5Survey Image

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Explore

6

Size Comparison

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7

Compare Stars

8

Spectral Classification

9

Hertzsprung-Russell Diagram

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Read: The Hertzsprung-Russell Diagram — Reading Stars Like a Map
10

Stellar Lifecycle

11

Blackbody Spectrum

12

Stellar Absorption Spectrum

Simulated absorption spectrum based on spectral type. Hover over lines to identify elements.

13

Stellar Fusion

Discover

14

Light Travel Time Machine

15

Relativistic Travel

Nearby in the Sky

Other targets within a few degrees — pan your scope a little and keep exploring.

Visibility scores assume a 150 mm Newton at Bortle 4.

Sigma CrB
HIP 79607; Sigma Coronae Borealis; 17 Coronae Borealis
Easy
Easy double, sep 7.4″
Double Star mag 5.64 1.6° Corona Borealis
M13
Great Hercules Cluster
Easy
Large bright globular cluster
Globular Cluster mag 5.8 4.8° Hercules
NGC 6207
Medium
Bright spiral galaxy
Galaxy mag 11.6 5.2° Hercules
30 Her
Easy
Mira-type variable, range 4.3–6.3
Variable Star mag 5.04 8.2° Hercules
Show on Map

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The Hertzsprung-Russell Diagram — Reading Stars Like a Map
The HR diagram turns the night sky into a physics map: every named star has a spot, every spot tells you mass, age, and fate. A guide for amateur observers.
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