This document discusses models for analyzing artificial sky brightness. It begins by defining sky brightness and noting that it is highly variable due to changing atmospheric conditions and light emissions. It then outlines several models for predicting night sky brightness, including two-stream approximation and iterative radiative transfer equation approaches. The document also discusses using analysis models to enable prediction and lists challenges for the future, such as extending measurement networks, using multispectral satellites, agreeing on common descriptors, developing parametric models, and issuing recommendations.