One 360th part of the circumference of a circle. The rough measure of an angle of one degree is the apparent diameter of a dime held at arm's length from the eye. The apparent diameter of the Sun and Moon is about 0.5°. The longest dimension of the bowl of the Big Dipper is about 10°. A degree is divided into 60 equal parts called minutes of arc. The length of a degree of latitude on the Earth's surface increases from 68.71 miles at the equator to 69.41 miles at 90°. The length of a degree of longitude on the Earth's surface varies from 69.65 miles at the Equator to 53.43 at 40°. Degrees are equally applicable to the Zodiac or the Ecliptic. As a time unit it is applicable to the Equator thus:
Degrees of Arc |
Hours and minutes of time |
360° |
24 h. |
30° (1 Sign) |
2 h. |
15° |
1 h. |
1° (60') |
4 m. |
1' (60") |
4 s. |
