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Gamma Crucis — Star in Crux

HR 4764; Gamma Crucis

Magnitude 6.4m Star Crux (Cru) Visible
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Observe

1Physical Properties

Magnitude 6.42
Spectral Type A3V
Star Color White (B-V 0.16)

2Position & Identifiers

RA 12h 31m 16.7s
Dec -57° 04' 52.0"
Constellation Crux (Cru)
HR 4764
HD 108925
SAO 240022
Bayer Gamma
Wikipedia

3How easy to spot?

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Equipment Bortle 3 Bortle 4 Bortle 5
Naked eye Hard V. hard+ V. 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 Feb – Apr (peak: Mar)

5Survey Image

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6

Compare Stars

7

Spectral Classification

8

Hertzsprung-Russell Diagram

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Read: The Hertzsprung-Russell Diagram — Reading Stars Like a Map
9

Stellar Lifecycle

10

Blackbody Spectrum

11

Stellar Absorption Spectrum

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

12

Stellar Fusion

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.

Gacrux
HIP 61084; Gamma Crucis
Easy
Cool red giant
Star mag 1.63 0.0° Crux
NGC 4337
Easy
Open cluster
Open Cluster mag 8.9 1.4° Crux
Mu Cru
Mu Cru (BS4898)
Easy
Easy double, sep 34.5″
Double Star mag 4.03 3.2° Crux
S Cru
Medium
Pulsating variable, period 4.7d
Variable Star mag 6.58 3.4° Crux
Blue planetary
NGC 3918
Medium+
Small bright planetary nebula
Planetary Nebula mag 8.0 5.6° Centaurus
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Explore Nightbase

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Arthur Eddington
1919 eclipse expedition confirming general relativity; first theory of stellar interiors; the Eddington limit
Biography
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.
Article
Crux
Mythology, bright stars, and deep-sky highlights.
Constellation
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