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40 Draconis — Double Star in Draco

Magnitude 6.0m DoubleStar Draco (Dra) Visible
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1Physical Properties

Magnitude 6.04
Spectral Type F7
Star Color Yellow (B-V 0.51)
Distance 130 ly

2Position & Identifiers

RA 18h 00m 03.4s
Dec +80° 00' 03.0"
Constellation Draco (Dra)
HR 6809
HIP 88127
HD 166865
SAO 8994
Flamsteed 40 Dra
Double Cat 11061
SIMBAD

3How easy to split?

Primary 6.0 mag Companion 6.7 mag Separation 19.3″
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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 19.3″
Companion Mag 6.7
Star Colors A: Yellow B: Yellow
Binary with HR 6810.

Eyepiece View

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

A: 6.0 · B: 6.7 · Sep: 19.3″ · PA: ? · 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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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

10.5217d, K 46.2k/s, V0 +2.9k/s, msin3i 0.462, asini 6.36.
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.

41 Dra
Easy
Easy double, sep 18.6″
Double Star mag 5.68 0.0° Draco
NGC 6643
Hard+
Bright spiral galaxy
Galaxy mag 11.1 5.5° Draco
74 Dra
Easy
Easy double, sep 214.4″
Double Star mag 5.96 6.1° Draco
Kappa Cep
Easy
Colorful double, sep 7.3″
Double Star mag 4.39 6.5° Cepheus
Show on Map

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