Mu Serpentis — Double Star in Serpens

Magnitude 3.5^m DoubleStar Serpens (Ser) Visible

Star Map + List + Plan

Observe

1Physical Properties

Magnitude 3.53

Spectral Type B9.5III giant

Star Color Blue-white (B-V -0.04)

Distance 170 ly

2Position & Identifiers

RA 15h 49m 37.2s

Dec -03° 25' 49.0"

Constellation Serpens (Ser)

HR 5881

HIP 77516

HD 141513

SAO 140787

Bayer Mu

Flamsteed 32 Ser

3How easy to split?

Primary 3.5 mag Companion 5.4 mag Separation 0.5″

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Telescope	Bortle 3	Bortle 4	Bortle 5
80 mm refractor 80mm refr.	V. hard	V. hard	V. hard
150 mm Newton 150mm Newt.	V. hard+	V. hard+	V. hard+
Celestron C8 (203 mm SCT) C8 203mm	V. hard+	V. hard+	V. 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 440 mm reflector.

4Visibility

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Best season Apr – Jun (peak: May)

5Multiple Star System

Separation 0.5″

Companion Mag 5.4

Position Angle 309°

Star Colors A: Blue-white B: Yellow-white

Discoverer CHR 259

Separation over time

Period: 71.1 y Eccentricity: 0.662 Now: 0.52", PA 306° + 0.07" in 5 years

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

Eyepiece View

Telescope Eyepiece

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80x Dawes: 1.9″ TFOV: 0.6°

Seeing

Scale Realistic = true angular size

A: 3.5 · B: 5.4 · Sep: 0.5″ · PA: 309° · N up, E right

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

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Size Comparison

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Compare Stars

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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

Discover

15

Light Travel Time Machine

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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.

Easy double, sep 3.4″

Double Star mag 5.35 8.3° Serpens

HIP 78738; Xi Scorpii

Tight double — a rewarding split at 1.2″

Double Star mag 4.77 8.7° Scorpius

Large bright globular cluster

Globular Cluster mag 5.8 9.5° Serpens

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