Directions for Making a Classroom Sundial Fig. 14. Dialface layout and cutout for gnomon
1. On a 3 x 5 card, lay out line DC perpendicular to IJ. 2. Place a protractor on D along DC and measure each hour angle for your latitude. Indicate each measure around the edge of the protractor with a dot. The morning hour angles are measured to the left of the noon line DC, and the afternoon hour angles, which are symmetric to those of the morning, are measured to the nght of the noon line. 3. Connect D with each dot. These are the hour lines, which are labeled from 6 A.M. at point I, through 12 noon at point C, and on to 6 P.M. at point J (see Figure 14a). 4. Measure angle CDB equal to your latitude (see Figure 14b, which is the same as Figure 14a but with the hour marks left out for clarity). Draw XY perpendicular to DC and in line with point B. Connect B with some point Z on line DC. Draw a semicircle using XY as its diameter.
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