The graphs above represent the sky conditions and local ambient temperature over the observatory.   The top graph is the sky condition vs. the Relative Sky Temperature.  The colder the "Rel. Sky Temp." the clearer the sky. 

The sky at the observatory site is defined as being clear (no clouds) when the graph falls below the dotted yellow line. This will appear as white on the graph.  Above the dotted red line is considered "Very Cloudy", this is the trigger point at which the dome's shutter will automatically close (approx -18 degrees).  This will appear as red on the graph. The dome will also close if a wet condition is detected (blue).   Any value between the red and yellow lines  is considered "Cloudy" and will be graphed in yellow.

 The most resent sky conditions appear to the right of the graph and the current sky conditions are displayed on the 2nd line at the top of the graph. The bottom graph represents the local ambient temperature as measured by the sensor.  The graph displayed on the webpage is updated approx once every 5 minutes. The weather station's  graph is updated in real time. 

The main purpose of the graph is to trend the changes of the sky's condition over time in order to calibrate (tweak) the cloud detector's accuracy.  It also allows me to accurately monitor the local sky conditions from a remote location.

 

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