Vertical Sundials

The vertical sundials  are the most common. Practically during the Middle Ages and Modern age , there was not one building official or religious nature, which does not have one in one of its walls of which today many of them are still standing. They are installed in walls with an orientation that can be anything, but to hit more hours, the dial must be placed in facing noon (south) walls. In this type of sundials, such as the horizontal, the gnomon is parallel to the axis of the earth, for it therefore should form with the vertical plane a complementary angle to the latitude of the settlement of the sundial, ie if the latitude was 50 °, the angle must have the gnomon to the plane of the dial is 40º (90-50 = 40)