Across
- 5. a circle on the surface of a sphere that is the curve of intersection of the sphere with a plane passing through its center
- 6. the time interval in which the phases repeat for example from full to full phase
- 9. Earth’s rotation period as defined by the position of the Sun in the sky; the time between successive passages of the Sun through the meridian
- 10. the angular distance north or south of the celestial equator
- 13. the coordinate for measuring the east-west positions of celestial bodies; the angle measured eastward along the celestial equator from the vernal equinox to the hour circle passing through a body
- 14. when a body rotates at the same rate that it revolves around another body, for example the moon
- 15. an arbitrary line on the surface of Earth near longitude 180° across which the date changes by one day
Down
- 1. an eclipse of the Sun by the Moon, caused by the passage of the Moon in front of the Sun
- 2. the period of the Moon’s revolution about Earth measured with respect to the stars
- 3. a great circle on the terrestrial or celestial sphere that passes through the poles
- 4. time based on the rotation of Earth
- 7. time as measured by the position of the Sun in the sky, for example this would be the time that would be indicated by a sundial
- 8. the different appearance of light and dark on the Moon as seen from Earth during its monthly cycle, from new moon to full moon and back to new moon
- 11. an eclipse of the Moon, in which the Moon moves into the shadow of Earth
- 12. Earth’s rotation period as defined by the positions of the stars in the sky; the time between successive passages of the same star through the meridian
- 16. alternate rising and falling of sea level caused by the difference in the strength of the Moon’s gravitational pull on different parts of Earth