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Aldulfin — Star in Delphinus

HIP 101421; Epsilon Delphini; 2 Delphini

Magnitude 4.0m Star Delphinus (Del) Visible
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1Physical Properties

Magnitude 4.03
Spectral Type B6III giant
Star Color Blue-white (B-V -0.13)

2Position & Identifiers

RA 20h 33m 12.8s
Dec +11° 18' 12.0"
Constellation Delphinus (Del)
HR 7852
HIP 101421
HD 195810
SAO 106230
Bayer Epsilon
Flamsteed 2 Del
SIMBAD Wikipedia

3How easy to spot?

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Equipment Bortle 3 Bortle 4 Bortle 5
Naked eye Easy Medium+ Medium
50mm finder Easy Easy Easy
150mm scope Easy Easy Easy
Easy Medium Hard Very hard Impossible

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

4Visibility

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Best season Jun – Aug (peak: Jul)

5Survey Image

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7

Size Comparison

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8

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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

Member of the local association (Pleiades group).
Deneb Dulfim; Deneb el Delphinus.

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 Del
Easy
Easy double, sep 214.6″
Double Star mag 5.05 1.9° Delphinus
C47
NGC 6934
Easy
Globular cluster — dense ball of ancient stars
Globular Cluster mag 8.9 3.9° Delphinus
EU Del
Easy
Semi-regular variable, range 5.8–6.9
Variable Star mag 6.25 7.1° Delphinus
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