Celestron CGE1100 Bedienungsanleitung PDF herunterladen (Seite 35)

Motion of the Stars

The daily motion of the Sun across the sky is familiar to even the most casual observer. This daily trek is not the Sun

moving as early astronomers thought, but the result of the Earth's rotation. The Earth's rotation also causes the stars to do

the same, scribing out a large circle as the Earth completes one rotation. The size of the circular path a star follows depends

on where it is in the sky. Stars near the celestial equator form the largest circles rising in the east and setting in the west.

Moving toward the north celestial pole, the point around which the stars in the northern hemisphere appear to rotate, these

circles become smaller. Stars in the mid-celestial latitudes rise in the northeast and set in the northwest. Stars at high

celestial latitudes are always above the horizon, and are said to be circumpolar because they never rise and never set. You

will never see the stars complete one circle because the sunlight during the day washes out the starlight. However, part of

this circular motion of stars in this region of the sky can be seen by setting up a camera on a tripod and opening the shutter

for a couple hours. The processed film will reveal semicircles that revolve around the pole. (This description of stellar

motions also applies to the southern hemisphere except all stars south of the celestial equator move around the south

celestial pole.)

Figure 5-2

All stars appear to rotate around the celestial poles. However, the appearance of this motion

varies depending on where you are looking in the sky. Near the north celestial pole the stars

scribe out recognizable circles centered on the pole (1). Stars near the celestial equator also

follow circular paths around the pole. But, the complete path is interrupted by the horizon.

These appear to rise in the east and set in the west (2). Looking toward the opposite pole, stars

curve or arc in the opposite direction scribing a circle around the opposite pole (3).

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Celestron CGE1100 Bedienungsanleitung Seite 35