So, you have an older Gentex mirror with a compass in it. These mirrors were originally made in the 90's.
Magnetic North has moved a bit since then. IF you notice that your mirror compass is not accurate, you can use these instructions to set a new setting with modern declinations.
- 01 = 30°E - 33°E
- 02 = 24°E - 30°E
- 04 = 14°E - 19°E
- 05 = 10°E - 14°E
- 06 = 09°E - 04°E
- 07 = 04°E - 00°
- 08 = 00° - 05°W
- 09 = 05°W - 09°W
- 10 = 09°W - 13°W
- 11 = 13°W - 17°W
- 12 = 17°W - 20°W
- 13 = 20°W - 24°W
- 14 = 24°W - 25°W
- 15 = 28°W - 32°W
These are approximate.
To get an up-to-date setting, ignore the manual and find a setting which corresponds with the declination at your intended location.
To find your current declination, you can use a GPS app on your phone this website, by providing an address. Magnetic Field Calculator Website
Original Declinations were derived from the NOAA Historical Magnetic Declination viewer, and attempting to map them as best as I could to the original instructions that came with these mirrors.
If you have information as to how these were actually derived for the settings, please either contact me or correct my information with a PR. I'll gladly update!
Initial commit.
These are approximated. I don't know the exact date these mirrors were made, or what year of information they were programmed with.