| 摘要 |
It is composed of two assemblies and an armature with a support. The first is formed by a double circular plane (1) corresponding to two antipodal horizons (2) and (3), a double circular semi-cylindrical rod representing the Local Meridian (4) and an axle as observed Local Vertical (5), perpendicular to the horizontal planes. The second is formed by three circular rods which represent the Celestial Equator (6) and the Tropics (7) and (8), and an axle normal to the plane of these circles or axis of the Poles (9). A semi-circular metallic armature (10) and an axle (11) which is common to the two systems or assemblies makes it possible for the second to move with respect to the first with an amplitude of rotation of from 0 DEG to 90 DEG , for the two to move on themselves, with an amplitude of 180 DEG . One variant of the model represents, by means of a spiral of 183 steps, the solar declination each day of the year. This model can be applied to primary and secondary teaching. <IMAGE>
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