In the
Bi-Polar model this is explained by the existence of two poles.
However, the Monopole model persists, and it would be interesting to try to debunk the explanation for it.
There might be a time when two of the three southern continent locations such as South America and Africa see the night stars at the same time, but never all three (South America, Africa and Australia) at the same time.
https://www.timeanddate.com/worldclock/sunearth.htmlHere is summer on June 21, 2021 with added green marker for "a star":
Translating it to a Flat Earth Monopole map, with relative location:
The star is close enough to those two locations to be in range so that the star could be visible at the same time from both locations.
As seen above, it is possible in some situations for two locations to see the same star at the same time. If the star is encircling the Earth like the Sun, then different observers will observe that star when it is night for that observer.
When each observer South America and Africa in the above diagram looks in a general sense to the south, they see the that star swirling around a southern celestial pole. The true star is displaced from due South for each observer, but it could be shifted to be more due South for the observer through the below light mechanism.
Logically it makes more sense that there is only one mechanism for multiple phenomena, rather than multiple mechanisms for multiple phenomena. In the Monopole model the appearance of the South Celestial Pole could be related to the seasons. On a Monopole Model the seasonal daylight patterns, where wide extents of the Earth receive daylight when the Sun moves to the South, can be explained with a magnifying dome model where the light creates broad shapes at different positions. Since we do not live in a perfect world, it does not necessarily follow that the Sun's area of light will make a circular shape at all times, or that the light of the Sun will necessarily engulf all of the Earth at once. If the light is shining through imperfect affecting phenomena it may bend upwards and widen into a non-circular shape. The upwards bending of light here also explains the general phenomena of night and day.
In the above, the seasonal daylight patterns of the Flat Earth Monopole Model are satisfactorily, and coincidentally, simulated with a magnifying dome.
If light behaves as if it were coming through a dome magnifying glass, another interesting aspect is that it is seen that the view from the underside of the dome can create an effect which could create a southern celestial system.
The Southern Celestial system is artificial, and only encompasses the stars around the true area of stars.
Since the stars are rotating over the Earth like the Sun, the night sky is over South America and Australia at different times, observers in those areas will see the same stars spinning around their observed South Celestial Pole when it is night for those areas. In the case of Africa and South America, they may be close enough together that the stars they see are the same stars, except moved more towards the South for each observer and located on one part or side of the apparent ring of stars than the other.