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Definition
| Distance in degrees above the horizon, for a star. |
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Definition
| A bright ring around the moon when it is lined up with the sun. |
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| The Earth's orbit at its furthest point from the sun. |
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Definition
| The Sun crosses the celestial equator moving southward at the autumnal equinox around September 22. |
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Definition
| How many degrees along the horizon a star is and corresponds to the compass direction. |
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Definition
| An imaginary circle directly above the Earth's equator. |
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Definition
| An imaginary sphere that surrounds the earth with all the stars scene at the same distance. |
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| Within an angular distance from the NCP equal to the observer's latitude are above the horizon for 24 hours |
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Definition
| Lines of longitude when projected onto the sky, measured in degrees |
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Definition
| The yearly path of the sun through the stars. |
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Definition
| The difference between apparent solar time and mean solar time. |
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Definition
| The number of degrees north or south of the Earth's equator. |
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Definition
| When an observer sees the Sun at its highest point above the horizon. |
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Definition
| The number of degrees east or west of the 0° longitude line that runs through Greenwich England. |
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Definition
| When the Sun-Moon angle is exactly 180 degrees and the Earth's shadow is covering the moon. |
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Term
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Definition
| A fictional sun that moves directly along the equator. |
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Definition
| The arc that goes through the north point on the horizon, zenith, and south point on the horizon. |
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Definition
| Point in the sky directly above the north pole. |
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Definition
| Outer region of partial shadow |
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Definition
| The Earth's orbit when it is closest to the sun. |
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Definition
| An effect that causes the Sun's vernal equinox point to slowly shift westward over time. |
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Definition
| The backwards movement of a planet. |
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Term
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Definition
| Backwards motion of a planet. |
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Definition
| Lines of latitude when projected onto the sky, measured in terms of hours, minutes, and seconds. |
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Term
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Definition
| A division of the year, marked by changes in weather, ecology, and hours of daylight. |
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Term
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Definition
| The stars movement around the Earth in 23 hours and 56 minutes |
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Term
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Definition
| The Moon drifts eastward with respect to the background stars (or it lags behind the stars). It returns to the same position with respect to the background stars every 27.323 days. |
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Term
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Definition
| The time required for the constellations to complete one 360° cycle around the sky and to return to their original point on our sky. |
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Term
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Definition
| The 24 hours it takes the sun to go from noon one day to noon the next day. |
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Term
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Definition
| The moon in a new phase and covering the sun at the same time. |
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Term
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Definition
| Point in the sky directly above the South Pole. |
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Definition
| For observers in the northern hemisphere, this is the farthest northern point above the equator. |
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Term
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Definition
| The moons phases from new (all shadow) to first quarter (1/2 appears to be in shadow) to full (all lit up) to third quarter (opposite to the first quarter) and back to new. This cycle takes about 29.53 days. |
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Term
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Definition
| Zones on the Earth 15 degrees apart, each with an hour time difference. |
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Definition
| The time interval between two sucessive vernal equinoxes. |
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Definition
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Definition
| The Sun crosses the celestial equator moving northward at the vernal equinox around March 21 |
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Term
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Definition
| For observers in the northern hemisphere, this is the farthest southern point below the equator. |
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