Hemispherical Paper Sundial for Latitude 30°S

Introduction

This document outlines the components and construction of a hemispherical paper sundial, a printable educational tool designed to track the sun's movement. This particular model is calibrated for use at a latitude of 30° South.

Components of the Sundial

The Bowl

The first component is the 'Bowl For Hemispherical Sundial'. This is presented as a flat pattern, or net, which, when cut and folded according to instructions, forms the main bowl-shaped structure of the sundial. The interior surface of the bowl is marked with lines that represent hours and divisions for different seasons, allowing for timekeeping and seasonal observation.

The Horizon Ring

The second component is the 'Horizon Ring For Hemispherical Sundial'. This is a circular piece designed to fit around the rim of the assembled bowl. It features markings for the months of the year (e.g., Jan, Feb, Mar... Nov, Dec) and indicates the cardinal directions, North and South. The ring also includes specific cut-out shapes that align with the bowl's segments, facilitating seasonal adjustments and accurate readings.

The Gnomons

The third set of components are the 'Gnomons For Hemispherical Sundial'. The primary diagram for the gnomon is circular, featuring radial lines and degree markings from 0 to 90. This diagram illustrates the 'Celestial Axis', a crucial element that aligns with the Earth's axis and points towards the celestial pole. It includes key reference points such as 'Solstice' and 'Equinox' markers, as well as indicators for 'Your Latitude' and a note about the sun's height at noon ("The sun is this high at noon."). Instructions like "Remove After Folding" are provided, indicating assembly steps. A secondary diagram shows the assembled gnomon structure, which is responsible for casting the shadow onto the sundial's surface.

Construction and Usage Notes

To ensure accurate timekeeping, the sundial must be assembled and oriented correctly for the user's specific latitude. The angle of the gnomon, for instance, should correspond to the local latitude. The seasonal markers on the bowl and horizon ring are designed to compensate for the sun's varying path throughout the year, particularly during the summer and winter solstices and the equinoxes.

This printable paper sundial model is provided by Astronomy For Thinkers.