| 摘要 |
The invention provides a tutorial device for observing lunar phase. A base sheet is inscribed with a time scale, a ring of moon pictures and a ring of moon phases. Outer circles on the base sheet define the months, and times of moonrise, moonset and moonsharp. Mounted on the base are a rotary segment shaped moonguide, a globe longitude disc and an elevation disc with a graduated moon angle scale and a pivoted elevation finger. The movable elements are used in conjunction with the fixed rings and circles on the base sheet to obtain moon data for selected times and earth longitudes.
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