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Mu Lupi — Double Star in Lupus

Magnitude 4.3m DoubleStar Lupus (Lup) Visible
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1Physical Properties

Magnitude 4.27
Spectral Type B8Ve
Star Color Blue-white (B-V -0.08)
Distance 251 ly

2Position & Identifiers

RA 15h 18m 32.0s
Dec -47° 52' 30.0"
Constellation Lupus (Lup)
HR 5683
HIP 74911
HD 135734
SAO 225638
Bayer Mu
SIMBAD

3How easy to split?

Primary 4.3 mag Companion 5.0 mag Separation 0.7″
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Telescope Bortle 3 Bortle 4 Bortle 5
80mm refr. V. hard V. hard V. hard
150mm Newt. V. hard+ V. hard+ V. hard+
C8 203mm Hard Hard Hard
Easy Medium Hard Very hard Impossible

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

To reach "Medium" at Bortle 3, you'd need at least a 330 mm reflector.

4Visibility

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Best season Apr – Jun (peak: May)

5Multiple Star System Triple E: optical

Components 3 (triple)
Component IDs AB
Separation 0.7″
Companion Mag 5.0
Companion Sp A
Position Angle 296°
Star Colors A: Blue-white B: Yellow-white
Discoverer HJ 4753
AB binary. C, 7.17V at 23" CPM.

Separation over time

Period: 772.0 y Eccentricity: 0.430 Now: 0.67", PA 108° -0.07" in 5 years
0.00" 0.21" 0.42" 0.63" 0.85" 2025 2030 2035 2040 2045 0.67"

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 296°

A: 4.3 · B: 5.0 · Sep: 0.7″ · PA: 296° · N up, E right

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

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7

Size Comparison

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8

Compare Stars

9

Spectral Classification

10

Hertzsprung-Russell Diagram

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Read: The Hertzsprung-Russell Diagram — Reading Stars Like a Map
11

Stellar Lifecycle

12

Blackbody Spectrum

13

Stellar Absorption Spectrum

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

14

Stellar Fusion

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15Stellar Notes

Possible Pleiades group; Sco-Cen assoc.
16

Light Travel Time Machine

17

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.

Kappa Lup
HIP 74376; Kappa1 Lupi
Easy
Easy double, sep 26.3″
Double Star mag 3.87 1.4° Lupus
Kappa Lup
HIP 74380; Kappa2 Lupi
Easy
Easy double, sep 26.6″
Double Star mag 5.69 1.4° Lupus
Pi Lup
HIP 73807; Pi Lupi
Medium
Tight double — a rewarding split at 1.6″
Double Star mag 4.72 2.4° Lupus
Pi Lup
HIP 73807; Pi Lupi
Medium
Tight double — a rewarding split at 1.8″
Double Star mag 4.82 2.4° Lupus
NGC 5927
Easy
Globular cluster — dense ball of ancient stars
Globular Cluster mag 8.3 3.2° Lupus
NGC 5925
Easy
Open cluster
Open Cluster mag 8.0 6.8° Norma
GG Lup
Medium
Eclipsing binary, period 1.8d
Variable Star mag 5.59 7.1° Lupus
Show on Map

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