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Mu Librae — Double Star in Libra

Observable Double Star Fair (27/100)

Sep: 2.0", Companion: mag 6.6

Magnitude 5.3m DoubleStar Libra (Lib) Visible
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1Physical Properties

Magnitude 5.31
Variable Type Alpha2 CVn (Magnetic Rotating)
Spectral Type A1pSrCrEu
Star Color White (B-V 0.07)
Distance 544 ly

2Position & Identifiers

RA 14h 49m 19.1s
Dec -14° 08' 56.0"
Constellation Libra (Lib)
HR 5523
HIP 72489
HD 130559
SAO 158821
Bayer Mu
Flamsteed 7 Lib
Double Cat 9396
SIMBAD

3How easy to split?

Primary 5.3 mag Companion 6.6 mag Separation 2.0″
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Telescope Bortle 3 Bortle 4 Bortle 5
80mm refr. Hard Hard Hard
150mm Newt. Medium+ Medium+ Medium+
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 Quintuple C,D: optical

Components 5 (quintuple)
Component IDs AB
Separation 2.0″
Companion Mag 6.6
Position Angle 8°
Star Colors A: White B: Yellow-white
Discoverer BU 106
AB and AE binary. B = Am(A2/A6/A8)s. C and D optical. E 12.5v at 27".

Separation over time

Period: 614.0 y Eccentricity: 0.650 Now: 2.0", PA 8° + 0.00" in 5 years
0.00" 0.57" 1.1" 1.7" 2.3" 2025 2030 2035 2040 2045 2.0"

Apparent separation over time, computed from ORB6 orbital elements. Steep curves indicate fast-changing pairs — catch them while they're splittable.

Eyepiece View

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80x Dawes: 1.9″ TFOV: 0.6°
Realistic = true angular size
N E 8°

A: 5.3 · B: 6.6 · Sep: 2.0″ · PA: 8° · N up, E right

At limit · Rayleigh: 2.3″ · Dawes: 1.9″ · Eff: 2.3″

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6

Size Comparison

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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

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14Stellar Notes

ADS 9396AB, Alpha CV.
Also classified A0III:pSrCr,s.
0.016".
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.

Zuben Elgenubi
HIP 72622; Alpha2 Librae; 9 Librae
Easy
Easy double, sep 230.8″
Double Star mag 2.75 1.9° Libra
NGC 5796
Hard
Elliptical galaxy
Galaxy mag 13.0 3.5° Libra
Zuben El Akribi
HIP 73473; Delta Librae; 19 Librae
Medium+
Eclipsing binary, period 2.3d
Variable Star mag 4.92 6.3° Libra
NGC 5634
Easy
Globular cluster — dense ball of ancient stars
Globular Cluster mag 9.6 9.5° Virgo
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