Stacked images of interstellar comet 3I/ATLAS acquired with UVOT, two visits. The first were obtained on 2025 July 31 and August 1 (visit 1, top half of figure) and the second on 2025 August 19 (visit 2, bottom half of figure). Images acquired with the V filter are shown on the left, with UVW1 images shown on the right. Source apertures used are shown in red, with the background sky annulus in dotted white. The UVW1 aperture is ≈20,000 km (10″) for July 31 and ≈19,000 (10″) km for August 19. Background annulus spans 122,000–184,000 km for visit 1 and 114,000–171,000 km for visit 2. Ticks along the edges mark 20″, with 2047 and 1908 km per arcsecond for each visit, respectively. Color scales are individually optimized for viewing. Inset grids are 10″ × 10″, centered on the nucleus.