Epsilon Octantis — Variable Star in Octans
Excellent (65/100)
Observe
1Physical Properties
Magnitude
5.10
Range
4.58 - 5.30
Period
55 days
Variable Type
Semi-Regular Variable (Late-type Giant)
Spectral Type
M5III
giant
Star Color
Red
(B-V 1.47)
2Position & Identifiers
RA
22h 20m 01.5s
Dec
-80° 26' 23.0"
Constellation
Octans
(Oct)
HR
8481
HIP
110256
HD
210967
SAO
258928
Bayer
Epsilon
Variable ID
Eps Oct
Querying VizieR catalog...
3How easy to follow?
Magnitude
4.6 – 5.3 mag
Amplitude
0.7 mag
Period
55 d
Type
SRB
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| Equipment | Bortle 3 | Bortle 4 | Bortle 5 |
|---|---|---|---|
| Naked eye Naked eye | Hard | Hard | V. hard+ |
| 50 mm finder 50mm finder | Medium | Medium | Medium |
| 150 mm telescope 150mm scope | Medium | Medium | Medium |
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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6Light Curve
7Comparison Stars for Epsilon Oct (4.6–5.3)
Nearby stable stars for estimating brightness (AAVSO)
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Explore
8
Size Comparison
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9
Compare Stars
10
Spectral Classification
11
Hertzsprung-Russell Diagram
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12
Stellar Lifecycle
13
Blackbody Spectrum
14
Stellar Absorption Spectrum
Simulated absorption spectrum based on spectral type. Hover over lines to identify elements.
15
Stellar Fusion
Discover
16Stellar Notes
SRb 4.58 - 5.30V, about 55d. Also called BO Oct.
Zeta Her group.
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
Variable Stars — A Guide for Observers
A practical guide to visual observation of variable stars: estimating magnitudes, finding comparison stars, recording data, and contributing to science with AAVSO.
Article
Octans
Mythology, bright stars, and deep-sky highlights.
Constellation
