| 摘要 |
A real-time solar observation system for Muslims comprises a camera (36) detecting sunlight (38) to produce image data, a camera (40) producing image data relating to a shadow cast by a vertical pole (42), and a processor (30) receiving image data from camera (36) and camera (40) and determining sunrise start (when the sun first appears) and finish (when the sun is first completely above the horizon), midday start (when the sun is at its zenith and the shadow is at its shortest) and finish (when the shadow has lengthened by the length of the pole), and sunset start (when the sun first starts to go below the horizon) and finish (when the sun is completely below the horizon). Three cameras may be used, or a single camera which is moved. If it is too cloudy, stored information may be used instead. Several systems may be networked. Audible or visible alarms may be given to a user, or he may be sent a cellular telephone message which activates a call to prayer, followed by another message when prayer may cease. |
