Alpha Capricorni — Star in Capricornus
HIP 100027; Alpha1 Capricorni; 5 Capricorni
Observe
1Physical Properties
Magnitude
4.24
Spectral Type
G3Ib
supergiant
Star Color
Orange
(B-V 1.07)
Distance
544 ly
2Position & Identifiers
RA
20h 17m 38.9s
Dec
-12° 30' 30.0"
Constellation
Capricornus
(Cap)
HR
7747
HIP
100027
HD
192876
SAO
163422
Bayer
Alpha1
Flamsteed
5 Cap
Double Cat
13632
Querying VizieR catalog...
3How easy to spot?
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| Equipment | Bortle 3 | Bortle 4 | Bortle 5 |
|---|---|---|---|
| Naked eye Naked eye | Medium+ | Medium+ | Medium |
| 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
Jun – Aug
(peak: Jul)
5Survey Image
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Explore
7
Size Comparison
Querying VizieR for stellar data…
8
Compare Stars
9
Spectral Classification
10
Hertzsprung-Russell Diagram
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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
Discover
15Stellar Notes
See note for HR 7754. ADS 13632B, 14v at 44"; C, 9.6v K5III, at 45" physical, vsini =<54k/s. D, 14.3v at 29" from C.
Prima Giedi; Algiedi Prima; Algedi with HR 7754.
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.
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The HR diagram turns the night sky into a physics map: every named star has a spot, every spot tells you mass, age, and fate. A guide for amateur observers.
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