Diurnal motion is an astronomical term referring to the apparent daily motion of stars in "orbit" around the Earth. It is important to note that stars only appear to be orbiting the Earth. Such motion can be shown by time-exposure[?]photography. Some of the more circumpolar stars may appear to be motionless.
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dB is the abbreviation for Decibel; see Bel
DB is a French automobile maker; see DB (car)
DB is the abbreviation for Deutsche Bahn, the major German ...