A sky brightness sensor is a device that helps to estimate the current condition in the sky above. Together with the sky temperature sensor (available separately), it creates a whole picture of both light pollution and the transparency of the sky.
The read values are presented in the AstroLink panel as sky brightness expressed in magnitude per square arc second, and also as estimated NELM – naked eye limiting magnitude. This sky sensor uses the same measuring cell that is used in Unihedron devices. Each device is photometrically calibrated with Meade ACF 10″ telescope and QHY163M camera. The actual reading may differ from other commercially available devices in terms of the offset. But the relative changes will be presented correctly. The sky brightness value is can be also displayed by any software that uses the ASCOM Observing Conditions interface (like Sequence Generator Pro or N.I.N.A.).
The operating range of the sensor is 16.00 – 22.50 mag / arcsec2. Values lower than 16.00 are also displayed in the panel, but accuracy is getting low in this range.
If you need to use more than two sensors (of any type) with AstroLink 4 USB, then you need to have also a sensor signal splitter (available separately).