Having a permanent observatory makes it easy to do astro-imaging on any clear night; however, it is critical that the user know what the weather is and will be ... or the expensive astro-imaging equipment could get soaked! The primary safety measure for most "real" remote observatories is the Boltwood Cloud Monitor; this is an infrared measurement device that can sense cloud layer thickness (by measuring the difference between the infrared emission from the sky and from the surroundings), and predict imminent rain - and automatically close the dome, irrespective of the power or computer status. However, Sierra Skies Observatory is usually operated from the house, and we do not yet have a Boltwood (or equivalent, such as the new AAG Cloud Monitor). However, we do monitor the weather carefully, and have recently installed a Davis Vantage Pro weather system.

The photo above shows the integrated weather system, which is fully wireless and provides temperature, humidity, rain, and wind measurements which are sent wirelessly to a data logger in the observatory. The data logger is, in turn, connected to the observatory computer, which downloads the data, and uploads image files (images of the weather gauges, etc.) to the web site.

The Vantage Pro is quite accurate (claimed to be NIST traceable), with temperature claimed to be accurate to 1 degree F, barometer to 0.03", and humidity to about 3-4%. The rain measurement is in units of 0.01". The lower white portion of the housing provides fan aspiration for air to circulate past the temperature sensor; in this way, direct heating of the system by the sun will not significantly alter the temperature readings. The solar panels provide power to the 24-hour aspiration fan, as well as to the microprocessor and RF electronics for wireless communications of the weather data. There is a 50' extension cord so that the anemometer can be remotely located (e.g., higher up), but at this point I have it mounted on the same 'mast' as the main unit.

The Vantage Pro console is able to read out all of the data from the weather station. It provides its own "inside" temperature (in our house), but the observatory inside temperature is actually measured by the data logger, and is not accessible from the console.

Weatherlink software from Davis is used to create web pages. The current (as of December 2010) Weather pages use templates supplied with the weather station, slightly edited for our use. The curent weather uploads every 5 minutes, and the historical weather uploads once per day. The system is capable of near real-time weather readings (so you can see the wind speed and direction change continuously) ... but I cannot currently access that, as this site is hosted by Apple, and they do not allow ftp; however, the Davis software ONLY provides ftp. So I am using an intermediate site, and the weather is only uploaded to this site when the weather page is clicked.

The data logger (which can be seen to the left of the Digital Loggers power controller on the 6th and 7th photos on this PAGE) is mounted to the inside wall of the observatory. While this is convenient, it may not be the final solution, as the walls (even though there is a double wall, there is no insulation in-between) heat up quite a bit in the summer (it gets to over 100 degrees F here), and I think the inside temperature readings may be higher than they should be, due to conductive heating of the data logger from the wall.