Compact light instrument, is intended for the measurement and the writing into the memory of the values of illumination beside different time intervals with the aid of the external sensor. Instrument is ideal for the rapid measurement and the writing into the memory of the fluctuations of illumination and to subsequent data processing on PK. The wide range of measurement from 2000 to 200000 Lux. Large volume of internal storage, to 32000 elements of data the possibility of connection based on PK on the means USB or RS-232 (option) and graphing regarding the obtained values.