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Theta Octantis — Star in Octans

Magnitude 4.8m Star Octans (Oct) Visible
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Observe

1Physical Properties

Magnitude 4.78
Spectral Type K3III giant
Star Color Red (B-V 1.27)
Distance 192 ly

2Position & Identifiers

RA 00h 01m 35.7s
Dec -77° 03' 57.0"
Constellation Octans (Oct)
HR 9084
HIP 122
HD 224889
SAO 258207
Bayer Theta
SIMBAD

3How easy to spot?

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Equipment Bortle 3 Bortle 4 Bortle 5
Naked eye Medium+ Medium Hard+
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 Aug – Oct (peak: Sep)

5Survey Image

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Explore

6

Size Comparison

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7

Compare Stars

8

Spectral Classification

9

Hertzsprung-Russell Diagram

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Read: The Hertzsprung-Russell Diagram — Reading Stars Like a Map
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

14

Light Travel Time Machine

15

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.

NGC 339
Hard+
Compact globular cluster
Globular Cluster mag 11.9 4.3° Tucana
NGC 220
Medium+
Open cluster
Open Cluster mag 11.0 4.4° Tucana
Epsilon Oct
Medium
Semi-regular variable, range 4.6–5.3
Variable Star mag 5.10 5.9° Octans
Lambda Oct
Easy
Easy double, sep 3.3″
Double Star mag 5.29 7.8° Octans
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