Finding South

To find North at night in the Northern Hemisphere you just look for the Polaris star near the Big Dipper. But in the Southern Hemisphere there is no star at the celestial pole. So the usual way is to locate the Southern Cross with it's 2 pointers and then go four and a half times the distance of the long axis to locate to point of the southern celestial pole.

This project creates a simple aid to help using the southern cross and its pointers to find south: Line the glow in the dark cross and pointers to the southern cross in the nights sky and the asterisk on the aid will be the direction of south. This works even as the stars appear to rotate overhead during the night.

The 'south celestial pole finder' is made from some aluminium from a beverage can.

Cut the top and bottom off a can, then down the middle. Straighten the can by moving it against an edge. I suppose some other sheet material could also be used but aluminium sheet is light weight and durable. It is also preferable to use a white can if possible as this will make the glow in the dark paint show up better.

Look up the Southern Cross constellation on the internet and print it out. Place this on top of the aluminium sheet and transfer the stars to it with a pen. Measure four and a half times length of the long axis and intersect this with a line out - half way between the pointers. This is the south celestial pole and the direction of south. Make an asterisk at this point.

Use glow in the dark paint to mark the stars of the southern cross, it's pointers and for the asterisk. The paint I used was left over from a rock painting kit but I expect you can also buy it from craft stores.

Shine a light on the glow in the dark paint for it to glow and then use the aid to locate south by lining it up with the Southern Cross. This will only work in the southern hemisphere as the southern cross is not visible in the northern hemisphere.