Subframe of image taken during the observation of the IIEV event on 28/09/2009 from Haleakala, Maui. The circular apertures indicate the regions of the frame where the background has been subtracted out in advance of the photometric reduction. Pixel values within the apertures have been multiplied by a factor of 8 for clarity. At the centre of each aperture lie Amalthea (“A”) and the star (“S”) used for differential aperture photometry of the satellite. Jupiter is off the left edge of the frame which coincides with the edge of the detector. The bright sources saturating the detector are, from left to right, Callisto and Europa. The entire subframe spans 512 × 404 pixels or 143″ × 113″.