A height of 0.5 inches is highly recommended. Default values are for the Kirkwood Observatory at Indiana University in the city of Bloomington, Indiana. Positive values represent angles north of the equator, and negative values are angles south of the equator. Positive values represent longitude values east of the Greenwich meridian. Negative values represent longitude values west of the Greenwich meridian.
Positive values represent longitude values east of the Greenwich meridian.
Negative values represent longitude values west of the Greenwich meridian. If you are near the equator, you might try a larger gnomon than the default. For mid to large latitudes a value of 0.5 inches is highly recommended. The value entered is in inches. These labels indicate the time that each line represents.