Bagnall Beach Observatory

MPC Observatory Code 433

The Boltwood Cloud Sensor determines “cloudiness” by measuring the difference between the temperature of the sky and the ambient temperature of the ground. A large negative number indicates clarity; a small negative, or even positive, number indicates cloudiness.

 

Information from the Cloud Sensor is interpreted and charted by a freeware application from Russell Croman’s Astrophtography. The top half of the graph has a yellow threshold at –25C for “cloudy” and a red threshold at –10C for “very cloudy”. In the event of the crossing of a threshold, the previous condition colour is plotted until the new condition has been maintained for a sufficient time interval. Rain is indicated by a blue line. The bottom half of the graph shows ambient temperature.

 

Please note the Boltwood Cloud Sensor is not designed to give accurate cloudiness readings during hours of daylight; although the rain detector works 24/7. Also please note that all times are in Coordinated Universal Time (UTC). This means the readings are current but the time given at the bottom of the graph is 10 hours behind Australian Eastern Standard Time (AEST), or 11 hours behind when daylight saving is in operation.

 

 

To convert to local time add 10 hours; or 11 hours during “summertime”.

Local time is:

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