Thank you for your video. Regarding 1:44 Magnetic Declination, for those who are unaware, Magnetic Declination can drift slowly over time depending on your location. Therefore allow your Sundial to be reoriented to True North if the Magnetic Declination has drifted significantly in the future.
True North itself in theory shouldn't drift, so once your sundial is aligned you shouldn't need to change it more than once every century or so. Magnetic North and South are very messy, in fact the Magnetic South Pole doesn't even have the decency to be within the boarders of Antarctica at present.
The easier way to do this is to just set it to the correct time. You do have to adjust for the Equation of Time, but it'll generally be more accurate than using a compass which will be affected by local magnetic objects.
You'd also have to calculate the difference between standard time and your local solar mean time because of your position within your time zone and DST (or get an app or friendly neighborhood astronomer to do it for you). I'd suggest using software like Stellarium to get the exact wall-clock time that the sun will next cross your meridian; say it's 1:31 PM tomorrow. Then tomorrow at 1:31, align the sundial so it reads noon. You could also go out at night at point the gnomen at Polaris. It's less than 1 degree away from true north, which is good enough for most people who are using their sundial largely as a garden decoration.
Greatt.. Umm I want to ask about this.. Well, since I'm at Southern Hemisphere, do I have to point the arrow exact to South celestial pole "which is true south" according to my latitude instead of north?.. Many thanks..
