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3 Centauri — Double Star in Centaurus

Magnitude 6.1m DoubleStar Centaurus (Cen) Visible
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1Physical Properties

Magnitude 6.06
Spectral Type B8V
Star Color Blue-white (B-V -0.04)
Distance 192 ly

2Position & Identifiers

RA 13h 51m 50.1s
Dec -32° 59' 41.0"
Constellation Centaurus (Cen)
HR 5211
HIP 67669
HD 120709
SAO 204916
Flamsteed 3 Cen
SIMBAD

3How easy to split?

Primary 6.1 mag Companion 6.0 mag Separation 7.9″
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Telescope Bortle 3 Bortle 4 Bortle 5
80mm refr. Easy Easy Easy
150mm Newt. Easy Easy Easy
C8 203mm Easy Easy Easy
Easy Medium Hard Very hard Impossible

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

4Visibility

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Best season Mar – May (peak: Apr)

5Multiple Star System

Separation 7.9″
Companion Mag 6.0
Position Angle 105°
Star Colors A: Blue-white B: Blue-white
See HR 5210.

Eyepiece View

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80x Dawes: 1.9″ TFOV: 0.6°
Realistic = true angular size
N E 105°

A: 6.1 · B: 6.0 · Sep: 7.9″ · PA: 105° · N up, E right

Resolved · Rayleigh: 2.3″ · Dawes: 1.9″ · Eff: 2.3″

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

14Stellar Notes

Sco-Cen stream.
Spectrum shows phosphorus.
15

Light Travel Time Machine

16

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.

3 Cen
Easy
Easy double, sep 7.8″
Double Star mag 4.56 0.0° Centaurus
4 Cen
Easy
Colorful double, sep 14.8″
Double Star mag 4.73 1.1° Centaurus
NGC 5397
Hard+
Elliptical galaxy
Galaxy mag 12.85 2.2° Centaurus
T Cen
Easy
Mira-type variable, range 5.5–9.0
Variable Star mag 6.05 2.2° Centaurus
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