Illustration of persistence in individual VIRCAM images. The top row shows a subsection of 3 NB118 images (DIT = 280 s, NDIT = 1) taken right after each other. The data are from detector 3, and the 3 subsections correspond to the same pixels on the detector. In between each image the telescope has moved, so the subsections correspond to different parts of the sky. The width of the section is 19′′, and the pixel scale is the native one of 0.34′ px^-1. In the first image a star of magnitude J_Vega = 11.1 (2MASS) is seen. In the subsequent two images, there is a persistent image at the same detector coordinates as the star in the first image. The bottom row shows the persistence masks created by our algorithm for each image, see text.