Arched equatorial sundial and use method thereof

The invention discloses an arched equatorial sundial and a use method, the sundial comprises a base, a latitude plate, a longitude plate, a sundial needle and a time ruler, the latitude plate and the longitude plate are both arc-shaped structures, latitude scales are arranged along the arc length direction of the latitude plate, longitude scales are arranged along the arc length direction of the longitude plate, and time scales are arranged along the length direction of the time ruler; the longitude plate is installed in the latitude plate, the longitude plate and the latitude plate are arranged in a longitude and latitude mode, the position, with the longitude scale value being 120, of the longitude plate coincides with the position, with the latitude scale value being 0, of the latitude plate, the time ruler is installed in the longitude plate and can move in the arc length direction of the longitude plate, the sundial is installed on the latitude plate in a string shape, and the latitude plate is installed