“Shift+stack” images, showing 49′ × 49′ cutouts centered on the dwarf planet (90377) Sedna (top; V ∼ 20.8, at a distance of 84 au) and dwarf planet candidate (455502) 2003 UZ₄₁₃ (bottom; V ∼ 20.7, at a distance of 43 au). These images were created by adjusting the images for the motion of the objects and stacking all 1108 images to add up the signals of these objects that are not visible in individual images. Three sets of background subtraction templates have been used: the median of all images (left), an h = 40, d = 10 donut (center), and an h = 160, d = 40 donut (right). The SNR (calculated using the sum of flux from the central 3 × 3 pixels) of each stack is in the titles. It is clear that the donut templates are better than the median template in both instances, but due to the very different distances of the two objects, different donut parameters work better for each of them. Pixel values are in electrons per second. The “z-scale” method was used to determine the color scale of each panel separately.