The data collected by "Pi of the Sky" cameras during cloudy nights is of lower quality. Because of that measurements of brightness and number of stars in the sky cannot be used for other analysis (i.e. searching variable stars) that require precision. The phase of the Moon is also an appreciable influence. Each camera can register the characteristic number of stars in one part of the sky which is called a field. To find this characteristic number it is necessary to investigate the distribution of the stars in each field, which allows us to prepare a criteria for qualifying the data.
In the section DISTRIBUTIONS you can find more information about these distributions and their application.