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39 Bootis — Double Star in Boötes

Observable Double Star Good (55/100)

Sep: 2.5", Companion: mag 6.7

Magnitude 5.7m DoubleStar Boötes (Boo) Visible
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1Physical Properties

Magnitude 5.69
Spectral Type F6V+F5V
Star Color Yellow (B-V 0.47)
Distance 362 ly

2Position & Identifiers

RA 14h 49m 41.3s
Dec +48° 43' 14.0"
Constellation Boötes (Boo)
HR 5538
HIP 72524
HD 131041
SAO 45231
Flamsteed 39 Boo
Double Cat 9406
SIMBAD

3How easy to split?

Primary 5.7 mag Companion 6.7 mag Separation 2.5″
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Telescope Bortle 3 Bortle 4 Bortle 5
80mm refr. Hard+ Hard+ Hard+
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 2.5″
Companion Mag 6.7
Companion Sp F5V
Position Angle 46°
Star Colors A: Yellow B: Yellow-white
Discoverer STF1890
Binary. Combined mag., color.

Separation over time

Period: 2114.2 y Eccentricity: 0.750 Now: 2.5", PA 46° -0.04" in 5 years
0.00" 0.73" 1.5" 2.2" 2.9" 2025 2030 2035 2040 2045 2.5"

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 46°

A: 5.7 · B: 6.7 · Sep: 2.5″ · PA: 46° · N up, E right

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

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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

ADS 9406B, 12.822d, K 58.3k/s, V0 -28.2k/s, msin3i 1.28, asini 9.47.
0.010".
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.

NGC 5689
Medium
Edge-on galaxy
Galaxy mag 11.9 2.3° Boötes
44 Boo
Medium
Eclipsing binary, period 6.4h
Variable Star mag 4.76 2.6° Boötes
Iota Boo
Easy
Colorful double, sep 38.8″
Double Star mag 4.75 6.0° Boötes
Kappa Boo
HIP 69483; Kappa2 Bootis; 17 Bootis
Easy
Easy double, sep 13.7″
Double Star mag 4.54 6.5° Boötes
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