Sun photometers for measuring spectral air transparency in stationary and mobile conditions

SP-9 and SPM multiwavelength sun photometers are described and briefly characterized. The SP-9 sun photometer is designed for year-round monitoring of the spectral air transparency in the 0.3–2.2 μm wavelength range in the regional network. To implement the automated measurement mode (unattended by operators), the instrument includes a solar sensor, an automatic sun pointing/tracking system, a built-in GPS detector, a flash drive, and sensors for meteorological parameters. The SPM portable photometer is a simplified version of SP-9 and is designed for the air transparency measurements in mobile conditions.