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103 Herculis — Star in Hercules

Magnitude 3.8m Star Hercules (Her) Visible
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1Physical Properties

Magnitude 3.83
Range 3.83 - 3.85
Variable Type BE
Spectral Type A0II-III bright giant
Star Color Blue-white (B-V -0.03)
Distance 338 ly

2Position & Identifiers

RA 18h 07m 32.6s
Dec +28° 45' 45.0"
Constellation Hercules (Her)
HR 6779
HIP 88794
HD 166014
SAO 85750
Flamsteed 103 Her
Variable ID Omi Her
SIMBAD

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 May – Jul (peak: Jun)

5Survey Image

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7

Size Comparison

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8

Compare Stars

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

Gamma Cas 3.81 - 3.9B, 4.1 - 4.2p.
H alpha emission.
16

Light Travel Time Machine

17

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.

100 Her
Easy
Easy double, sep 14.4″
Double Star mag 5.86 2.7° Hercules
104 Her
Easy
Cool red giant
Star mag 4.97 2.8° Hercules
NGC 6482
Medium+
Elliptical galaxy
Galaxy mag 11.3 6.7° Hercules
T Lyr
Easy
Variable star, range 7.5–9.2
Variable Star mag 7.50 9.7° Lyra
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