It doesn't.
The gnomon is supposed to match the latitude of the location where the sundial is placed. If the latitude is 30 degrees and the gnomon is 45 the entire sundial will have to be tilted to keep correct time.
Another way to describe this is to say that the gnomon should be parallel to the Earth's axis.
gnomon
The pin of a sundial is called a gnomon. It is the part of the sundial that casts a shadow onto the dial face to indicate the time.
the shadow of the sundial is just called a shadow
The pin of a sundial where the shadow falls is called the gnomon. It is typically a thin, straight rod that extends vertically from the sundial's base. The shadow cast by the gnomon is used to indicate the time of day on the sundial's face.
The raised arm of a sundial that indicates the time of day by its shadow is the gnomon (NO-mon). A sundial has but one arm, what do you mean by secondary arm?
gnomon
The pin of a sundial is called a gnomon. It is the part of the sundial that casts a shadow onto the dial face to indicate the time.
The vertical pointer on a sundial is the gnomon.
the shadow of the sundial is just called a shadow
The pin of a sundial where the shadow falls is called the gnomon. It is typically a thin, straight rod that extends vertically from the sundial's base. The shadow cast by the gnomon is used to indicate the time of day on the sundial's face.
gnomon
index?
The raised arm of a sundial that indicates the time of day by its shadow is the gnomon (NO-mon). A sundial has but one arm, what do you mean by secondary arm?
The stationery arm of a sundial is called the "gnomon." It is the part that casts a shadow onto the dial face to indicate the time.
The rod in the center of a sundial is called a gnomon. It is the part of the sundial that casts a shadow, allowing the time to be determined based on the position and length of the shadow it creates.
The raised arm of a sundial that indicates the time of day by its shadow is the gnomon (NO-mon). A sundial has but one arm, what do you mean by secondary arm?
The pointer on a sundial is called a gnomon. It casts a shadow on the sundial face to indicate the time.