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5 Aquilae — Double Star in Aquila

Observable Double Star Excellent (64/100)

Sep: 12.5", Companion: mag 7.0

Magnitude 5.9m DoubleStar Aquila (Aql) Visible
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1Physical Properties

Magnitude 5.90
Spectral Type A2Vm
Star Color White (B-V 0.13)
Distance 362 ly

2Position & Identifiers

RA 18h 46m 28.5s
Dec -00° 57' 42.0"
Constellation Aquila (Aql)
HR 7059
HIP 92117
HD 173654
SAO 142606
Flamsteed 5 Aql
Double Cat 11667
SIMBAD

3How easy to split?

Primary 5.9 mag Companion 7.0 mag Separation 12.5″
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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 May – Jul (peak: Jun)

5Multiple Star System Triple

Components 3 (triple)
Component IDs AB
Separation 12.5″
Companion Mag 7.0
Position Angle 121°
Star Colors A: White B: Yellow-white
Discoverer STF2379
AB binary, B, Am, F3Vm, or Am(A5/F1/F2), RV +9.2k/s, vsini =<25k/s. C, 11.3v optical.

Separation over time

Measured 1796 → 2019 (223 y)
Separation drift 11.2" → 12.5" (+1.30")
Rate +0.0058" / y
PA drift 122° → 121° (-1°, -0.004°/y)

Slow change over generations — observable in lifetime comparisons.

Measured from the WDS observational archive. No orbital solution has been derived — most likely the period is too long to fit an orbit to the available measurement arc.

Eyepiece View

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80x Dawes: 1.9″ TFOV: 0.6°
Realistic = true angular size
N E 121°

A: 5.9 · B: 7.0 · Sep: 12.5″ · PA: 121° · 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

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8

Spectral Classification

9

Hertzsprung-Russell Diagram

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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 11667A, spectrum binary, RV var.? Unresolved by speckle interferometry on 1976.30; companion with sep. 0.13" seen | on 1980.48 (McAlister and Hartkopf).
Sirius group; UMa stream.
Also classified Am(A1/A7V/A7).
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 6704
Easy
Open cluster
Open Cluster mag 9.2 4.4° Scutum
R Sct
Easy
Mira-type variable, range 4.5–8.2
Variable Star mag 5.20 4.8° Scutum
59 Ser
Easy
Easy double, sep 3.9″
Double Star mag 5.21 5.0° Serpens
NGC 6749
Medium
Globular cluster — dense ball of ancient stars
Globular Cluster mag 11.1 5.5° Aquila
Alya
HIP 92946; Theta1 Serpentis; 63 Serpentis
Easy
Easy double, sep 22.4″
Double Star mag 4.62 5.7° Serpens
Theta Ser
HIP 92951; Theta2 Serpentis; 63 Serpentis
Easy
Easy double, sep 405.6″
Double Star mag 4.98 5.7° Serpens
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