A battery powered cloud sensor, perfect for portable use.

• Detects cloud and daylight
• Audible alert
• Battery powered
• Standalone operation
• Not intended for permanent installation

The Boltwood Portable Cloud sensor can be set to alarm when the skies clear, so you can commence observations. It can also be set to sound the alarm when clouds appear, alerting you to possible risk to your automated observing equipment.

The Portable Cloud Sensor consists of a sensor head and a control box, connected by a cable. The sensor head is placed outside, pointing up at an unobstructed sky. The control box can be conveniently located inside a tent or building, as needed. The control box includes batteries that will power the unit for over 100 hours, plus an alarm beeper, a headphone jack for “silent” alarms, and simple user controls.

The Portable Cloud Sensor measures the amount of cloud cover by comparing the temperature of the sky to the ambient ground level temperature. The sky temperature is determined by measuring the amount of radiation in the 8 to 14 micron infrared band. A large difference indicates clear skies, whereas a small difference indicates dense, low-level clouds. This allows the sensor to continuously monitor the clarity of the skies, and to alert the user when conditions change.

A built-in daylight sensor is also included. When the sensor is set to detect “Clear & Dark” conditions, it will alarm for clear skies unless the sun comes up first, in which case it lets you sleep in. When the sensor is set to detect “Cloudy or Light” conditions, it will alert you when clouds roll in or dawn approaches, so you can protect your telescope against the elements (including the sun!).

Although the Portable Cloud Sensor uses the same cloud detection technology as it’s big cousin, the Boltwood Cloud Sensor III, it is not designed for permanent installations. It does not detect rain/moisture, wind, or humidity. The sensor is gently heated to prevent dew or frost, but it does not have the power to clear itself after a rain shower; it must be wiped off. It cannot connect to a computer or trigger an observatory dome closure. For permanent installations please use the Boltwood Cloud Sensor III.

The control box, shown at left, can be conveniently located remotely from the sensor head.  The simple user controls let you set the cloudy/clear threshold, set it to alarm for clear or cloudy conditions, and turn it on/off. On the side are two jacks; one for the sensor cable and one for optional headphones (not included).

Includes Sensor Head, Control Box, and Cable.