Sky sensor device

A method comprising:

• controlling a camera sensor to capture a series of exposure-bracketed images having a first dynamic range and generate an image from the series of exposure-bracketed images, the image having a second dynamic range higher than the first dynamic range;
• controlling an illuminance sensor to measure a global illuminance value;
• determining a global horizontal diffuse value based on at least the image;
• and
• determining a direct normal illuminance (DNE) value using the global illuminance value and the global horizontal diffuse value.

A computing system comprising:

• a memory;
• and
• a processing device operatively coupled to the memory, wherein the processing device is to:
• control a camera sensor to capture a series of exposure-bracketed images having a first dynamic range and generate an image from the series of exposure-bracketed images, the image having a second dynamic range higher than the first dynamic range;
• control an illuminance sensor to measure a global illuminance value;
• determine a global horizontal diffuse value based on at least the image;
• and
• determine a direct normal illuminance (DNE) value using the global illuminance value and the global horizontal diffuse value.