Subsection images (1′ × 1′) of the field of AT 2018cux in NGC 3256. a) EFOSC2 i-band discovery image () of AT 2018cux, b) EFOSC2 pre-discovery image (), and c) Subtraction between the images. The locations of SN 2018ec and AT 2018cux are shown with tick marks in all the panels. Since the reference image contains increased flux from SN 2018ec compared to that of the AT 2018cux discovery image, the colour scale of the two events is reversed in the subtraction. The image scale and orientation are indicated in the left panel.