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The south celestial pole over the Very Large Telescope [3] Locating the south celestial pole. The south celestial pole is visible only from the Southern Hemisphere. It lies in the dim constellation Octans, the Octant. Sigma Octantis is identified as the south pole star, more than one degree away from the pole, but with a magnitude of 5.5 it is ...
A pole star is a visible star that is approximately aligned with the axis of rotation of an astronomical body; that is, a star whose apparent position is close to one of the celestial poles. On Earth , a pole star would lie directly overhead when viewed from the North or the South Pole .
The negative pole is the pole toward which the thumb points when the fingers of the left hand are curled in its direction of rotation. This change was needed because the poles of some asteroids and comets precess rapidly enough for their north and south poles to swap within a few decades using the invariable plane definition.
The south celestial pole currently lacks a bright star to mark its position, but over time precession also will cause bright stars to become South Stars. As the celestial poles shift, there is a corresponding gradual shift in the apparent orientation of the whole star field, as viewed from a particular position on Earth.
For most purposes, the Geographic South Pole is defined as the southern point of the two points where Earth's axis of rotation intersects its surface (the other being the Geographic North Pole). However, Earth's axis of rotation is actually subject to very small "wobbles" ( polar motion ), so this definition is not adequate for very precise work.
This yields a kind of star-trail image. The beginning and the end of the star trails must be clearly marked with a few seconds of static exposure. Due to the rotation, the information about the current direction of the axis is hidden in the image. Alternatively, two static images can be taken, which differ by a rotation around the polar axis.
Sigma Octantis is a solitary [9] star in the Octans constellation that forms the pole star of the Southern Hemisphere.Its name is also written as σ Octantis, abbreviated as Sigma Oct or σ Oct, and it is officially named Polaris Australis (/ p oʊ ˈ l ɛər ɪ s ɔː ˈ s t r eɪ l ɪ s /). [10]
A star chart of the entire Southern Sky, centered on the south celestial pole. The southern celestial hemisphere, also called the Southern Sky, is the southern half of the celestial sphere; that is, it lies south of the celestial equator.