SDSSr filter brightness of the coma of 41P over time. Top panel: apparent coma brightness versus time (in Julian Date) measured in an aperture corresponding to 5000 km at the distance of the comet. Measurement uncertainties are typically of the size of the plotted symbols. Bottom panel: coma brightness in a 5000 km aperture scaled to 1 AU Earth distance (blue dots), and additionally corrected for a linear phase function with a slope of 0.04 mag deg⁻¹ (red dots). Perihelion passage of 41P happened on Julian Date 247 856.24959 (2017 April 12).