Southern Celestial Hemisphere
The Southern Celestial Hemisphere or the Southern Sky, is part of a rotating astronomical region in the sky. It is the southern hemisphere of the celestial sphere.
Astronomy
In the context of astronomical discussions or writing about celestial mapping, it may also simply then be referred to as the Southern Hemisphere.
For the purpose of celestial mapping, the sky is considered by astronomers as the inside of a sphere divided in two halves by the celestial equator. The Southern Sky or Southern Hemisphere is therefore that half of the celestial sphere that is south of the celestial equator. Even if this one is the ideal projection of the terrestrial equatorial onto the imaginary celestial sphere, the Northern and Southern celestial hemispheres must not be confused with descriptions of the terrestrial hemispheres of the Earth itself.
Visibility from the Northern terrestrial hemisphere
Due to the angled rotation of the Earth relative to the ecliptic, parts of the Southern Sky are visible from the Northern terrestrial hemisphere at certain times of the year.