3 Equulei — Star in Equuleus
Observe
1Physical Properties
Magnitude
5.61
Spectral Type
K5III
giant
Star Color
Red
(B-V 1.65)
Distance
297 ly
2Position & Identifiers
RA
21h 04m 34.7s
Dec
+05° 30' 10.0"
Constellation
Equuleus
(Equ)
HR
8066
HIP
104031
HD
200644
SAO
126518
Flamsteed
3 Equ
Querying VizieR catalog...
3How easy to spot?
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| Equipment | Bortle 3 | Bortle 4 | Bortle 5 |
|---|---|---|---|
| Naked eye Naked eye | Hard+ | Hard+ | Hard |
| 50 mm finder 50mm finder | Easy | Easy | Easy |
| 150 mm telescope 150mm scope | Easy | Easy | Easy |
Easy
Medium
Hard
Very hard
Impossible
Bortle 3 = rural · 4 = outer suburbs · 5 = suburbs
4Visibility
Set a location in User Settings to see visibility data.
Best season
Jul – Sep
(peak: Aug)
5Survey Image
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Explore
6
Size Comparison
Querying VizieR for stellar data…
7
Compare Stars
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
Discover
14Stellar Notes
Some early sources called this Zeta Equ. Not retained. Not Zeta in Bayer.
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.
Explore Nightbase
Related knowledge, tools, and stories — no observation planning required.
Arthur Eddington
1919 eclipse expedition confirming general relativity; first theory of stellar interiors; the Eddington limit
Biography
Equuleus
Mythology, bright stars, and deep-sky highlights.
Constellation
The Life of Stars
From birth in a nebula to spectacular death — how stars are born, shine, swell, and die, and how to read the clues in their starlight.
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