In our most recent paper (Vondrak and Ron, 2017) we proposed a new method of determining the parameters (period T, Q-factor) of Free Core Nutation that is not part of the IAU 2000 model of nutation, and therefore present in observed celestial pole
The south celestial pole
can be found midway along the line joining Crux to Achernar.
The top edge of the gnomon (the pointy bit) needs to be aligned with the celestial pole
for either type, so it's parallel to the Earth's axis.
Polaris is an averagelooking star which just happens to appear close in the sky to the north celestial pole
Pole to celestial pole
, through wind like desert sand, an adamantine
3, in which the gnomon is once again pointing to the South Celestial pole
, whose shadow is cast onto a plane inclined at 15 [degrees] to the horizon.
Immediately above the celestial pole
is the faint constellation of Camelopardalus which, despite being the eighteenth largest by area in the sky, contains no stars brighter than fourth magnitude.
To compensate for your local latitude, your sundial's pointer, or gnomon, that casts the shadow on the hour marks should point towards the celestial pole
(the north celestial pole
if you're in the Northern Hemisphere, the south celestial pole
if you're in the Southern Hemisphere).
This brings you close to Polaris, located just 2/3[degrees] from the north celestial pole
. The constellations in the northern sky wheel around and around this point.
Like our counterparts in the southern hemisphere, we were driven to observe near the celestial pole
; in our case, the North Celestial Pole
(NCP) was the only part of the northern hemisphere sky available for round-the-clock observations.
For those of us living in the middle latitudes of Europe and North America, the lens of choice should be a wide-angle--24-35 millimetres--which will provide enough coverage in the frame to include the celestial pole
as well as the horizon with its landform silhouetted against the sky.
If you draw an imaginary line from Achernar to the Southern Cross, then the South Celestial Pole
lies at about halfway along this line.