This page contains more detailed information about sensors located on the roof and about indications on 'Weather Monitor' and on EPICS screens.
* "Rain Collector" is a big black bowl installed on the roof. It has an opening in the bottom of the bowl which should be sometimes cleaned using napkins and water, otherwise all access to rain sensors would be clogged. It is written in the "Davis" manual that the Rain Collector should be cleaned at least once or twice a year. It is recommended to separate the cone of the Rain Collector from the base before cleaning and use soapy water for cleaning the internal parts.
Indications of the amount of precipitation on the 'Weather Monitor' and on the EPICS screens will not disappear by themselves shortly after the rain. They are kept in memory until someone clears them from the 'Weather Monitor' located on the north wall of the interferometer room. See below a photo of the page from "Davis" manual explaining how to clear the information.
As described in the "Davis" manual, you can access information about either "Daily rainfall" or "Total rainfall" on the 'Weather Monitor'. Only "Total Rainfall" information is transferred to UNIX computers, "Total Rainfall" is what you see on the EPICS screen, so if you want to clear the indication on the EPICS screen, you should clear "Total rainfall" on the 'Weather Monitor'.
* "Temperature/Humidity Sensor" is a small yellow plastic box located below the Rain Collector in a place, protected from direct sun. It is written on the box "Temperature/Humidity module", so it should provide information about the outside humidity, but as of April 18 2008 this information is not indicated neither on the 'Weather Monitor' nor on the EPICS screens.