The robotic software depends upon knowing whether it's cloudy or not, both to protect the telescope from sudden rain showers and to prevent the system from taking lots of pictures of the undersides of dark clouds rather than of the sky.

MONET uses a Boltwood II cloud sensor built by Cyanogen Inc., a simple device which simply measures the temperature of the sky via its infrared brightness (like a household motion sensor) and comparing it with the ambient temperature.  Unfortunately, this sensor is currently broken and may have to be  fixed or replaced, a simple process which nevertheless may take a week or two.  Until then, MONET will not be able to observe robotically.

Boltwood II cloud sensor

2014-JUN-18 UPDATE: the McDonald observing support staff have performed a miracle and fixed the cloud sensor! 

2014-JUN-24 UPDATE: cloud sensor is broken again, we're now using the one from LCOGT.