AAG Cloudwatcher

Far too often the clouds clear at 1 or 2 in the morning, and opportunities to image are lost.
With this in mind I have bought an AAG Cloudwatcher which will be able to alert me to any such clear periods.

  The device can detect sky brightness, rain, and the presence or absence of cloud cover.

Cloud detection is done by an infra red measurement of sky temperature. Clouds will appear to be warm, but a clear sky will appear to the sensor at a temperature of -20 to -30 degrees.

The rain sensor (the large circle) is heated, so condensation does not form, and any moisture from rain will soon evaporate.

  The cloudwatcher mounted on a mast. Although the device is designed to be permanently exposed to the weather, the UK climate is such that some protection may be advisable.
A simple box cover on a lever is shown.

   The cover retracted.

  An example of a brief rain shower.

  Approaching darkness.

  October 6th
Perfectly clear blue sky - correctly identified!

Cloudwatcher reports the sky temperature as -27.5 °C

This image is from a 'Remote' computer. The 'Master' computer is in the observatory.