The Southern Cross, or the Constellation of Crux – as the name implies – is visible in the Southern Hemisphere. It consists of the Southern Cross and the two pointers: Alpha-(Rigil Kent) and Beta-Centauri (Hadar). Finding direction in True South with the Southern Cross is easy. First, the correct Southern Cross has to be found in the night sky. Other cross-like constellations of stars resemble the Southern Cross. These, however, are larger and do not have the two distinctive pointers.
When the correct Southern Cross is found, the distance between Gamma Crux (Gacrux) and Alpha Crux (Acrux) will be extended 4,5 times along this line. From that point, a vertical line would be drawn down to the horizon, showing True South. This crossing point is called ‘South Celestial Point’.
As an alternative and more precise method, a line from Gacrux to Acrux can be drawn and extended into space. After that, a second line is drawn perpendicular from the middle of the connection between Hadar (Beta-Centauri) and Rigil Kent (Alpha-Centauri)—the two pointers. The Celestial South Pole is vertically below the True South, where these two extension lines meet.
This second alternative is better suited for drawing lines on a kitchen table. Extending the long Crux axis four times in the field is sufficient for finding the True South (First method).
Another possibility of finding the true South is locating Scorpio in the night sky, as described in this article on this website. The constellation of Orion is described here.
Lessons learned for finding True South with the Southern Cross
- It is essential to find the correct Southern Cross in the night sky by practicing and memorizing the Constellation picture, including the two pointers
- Extending the long axis (Gamma-Cruz – Alpha Cruz) 4,5 times will result in finding the Celestial South Pole and vertically down True South.
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