Abstract: Systems and methods for off-axis detection of a laser source. The system may include an optical sensor configured to detect light, a focusing lens adjacent to an input of the optical sensor and configured to focus the light and an optical filter adj acent to an input of the focusing lens and configured to filter a wavelength of the light. A processor may be connected to the optical sensor and may implement disclosed methods to analyze data from the optical sensor to detect atmospheric scattering of laser light from the laser source.