Octant (constellation)
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Octant constellation |
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| Latin name | Octane |
| Latin genitive | Octantis |
| Abbreviation | Oct |
| Right ascension | 00 h 00 m 00 s to 24 h 00 m 00 s |
| declination | −90 ° 00 ′ 00 ″ to −74 ° 18 ′ 14 ″ |
| surface | 291.045 deg² rank 50 |
| Completely visible | 6 ° S to 90 ° S |
| Observation time for Central Europe | not visible |
| Number of stars brighter than 3 mag | 0 |
| Brightest star (size) | ν octantis (3.76) |
| Meteor streams |
no |
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Neighboring constellations |
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| swell | IAU , |
 The Octans constellation as seen with the naked eye |
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The octant ( Latin octans ) is the southernmost constellation in the night sky.
description
The octant is an inconspicuous constellation on the southern celestial pole . In contrast to its northern counterpart, the Little Bear with the bright star Polaris , there is no conspicuous star near the south celestial pole. The closest star σ Octantis (also called Polaris Australis) visible to the naked eye is a 5th magnitude star .
history
The constellation was introduced in 1752 by the French astronomer and mathematician Nicolas Louis de Lacaille . From 1750 to 1754 de Lacaille in South Africa measured the positions of over 10,000 stars in the southern sky near Cape Town . During these observations he created 14 new constellations. The octant constellation is one of them. It is supposed to represent an octant , an instrument that was previously used by seafarers to determine their position. On Johann Elert Bode 's Uranographia from 1801, de Lacailles' new constellation appeared under the name "Octans Nautica".
Celestial objects
Stars
| B. | F. | Names or other designations | size | Lj | Spectral class |
|---|---|---|---|---|---|
| ν | 3.76 m | K0 III | |||
| β | 4.13 m | A9 IV / V | |||
| δ | 4.31 m | K2 III | |||
| θ | 4.78 m | K2 III | |||
| ε | 5.09 m | M6 III | |||
| γ 1 | 5.10 m | G7 III | |||
| α | 5.13 m | F4 III | |||
| λ | 5.27 m | G8 / K0 III | |||
| γ 2 | 5.29 m | K1 / K2 III | |||
| ξ | 5.32 m | B6 IV | |||
| ζ | 5.43 m | F0 III | |||
| ι | 5.45 m | K0 III | |||
| σ | Polaris australis | 5.45 m | F0 III | ||
| φ | 5.47 m | A0 V | |||
| ψ | 5.49 m | F3 III | |||
| τ | 5.50 m | K2 III |
ν Octantis, the brightest star in the octant, is a 690 light-years distant, orange star of the spectral class K0 III.
β Octantis is 140 light years away. It is a white shining star of the spectral class A9 IV.
σ Octantis is 270 light years away. With an apparent brightness of 5.45 m , it is barely visible to the naked eye.
The Latin name Polaris Australis means "southern pole star".
NGC objects
| NGC | other | size | Type | Surname |
|---|---|---|---|---|
| 2573 | Galaxy | |||
| IC 4333 | Galaxy | |||
| IC 4864 | Galaxy | |||
| IC 4912 | Galaxy | |||
| 6438 | Galaxy | |||
| 7098 | Galaxy | |||
| Mel 227 | Open star cluster |
See also
Web links
Individual evidence
- ↑ Constellation Octant. In: Günther Bendt, Baader Planetarium GmbH, D-82291 Mammendorf. 2019, accessed November 19, 2019 .