Finding North

One of the things we must do before we lay the tiles on the sundial is to find true north.

True north is not the same thing as magnetic north. If you use a compass to find north on a large sundial, the sun shadow will be inaccurate. This is because of magnetic declination, (sometimes called magnetic variation) which is the angle between magnetic north and true north. Magnetic declination changes over time and with location. If you use a compass to find north, you must correct for your particular declination.

For the latitude and longitude at Aurora 7 schoolyard, according to the NOAA site, the declination is = 9° 5' E changing by 0° 8' W/year.You can also find north by casting shadows and measuring them. Click on this for how.
Or we can cast a shadow at exactly noon (or 1:00, with an hour added for Daylight Savings time) because the sun will be exactly south at that particular time, and the shadow will be exactly north.

Another method is to go out on a clear night and look for the north star.

Because we are gong to measure north by casting a shadow, we are using a large tripod on the sundial. A big object= a big shadow. You can tell your friends that is what the tripod is doing.