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Tau Herculis — Star in Hercules

Magnitude 3.9m Star Hercules (Her) Visible
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1Physical Properties

Magnitude 3.89
Spectral Type B5V
Star Color Blue (B-V -0.15)
Distance 307 ly

2Position & Identifiers

RA 16h 19m 44.4s
Dec +46° 18' 48.0"
Constellation Hercules (Her)
HR 6092
HIP 79992
HD 147394
SAO 46028
Bayer Tau
Flamsteed 22 Her
Double Cat 10010
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 Apr – Jun (peak: May)

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

3.85 - 3.90V.
ADS 10010AB, 6700y.
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.

42 Her
Hard+
Cool red giant
Double Star mag 4.90 4.1° Hercules
IC 1153
Hard+
Bright spiral galaxy
Galaxy mag 12.72 4.3° Hercules
30 Her
Easy
Mira-type variable, range 4.3–6.3
Variable Star mag 5.04 4.7° Hercules
NGC 6229
Easy
Globular cluster — dense ball of ancient stars
Globular Cluster mag 9.4 4.8° Hercules
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