Wide-survey difference imaging in the Dark Energy Survey

The difference imaging technique is applicable to a wide range of problems in time-domain astronomy, such as supernovae studies, transient and moving object searches, and optical followup of gravitational wave triggers. The technique involves subtracting template images from search images in order to identify any point sources in the search images that are not present in the templates. The Dark Energy Survey (DES) normally employs the technique in its supernova program; we here apply it to approximately 6500 images in four filters taken during the sixth DES observing season in 2018-2019. We will briefly review the difference imaging technique and the challenges in extending it to the wide survey program before concluding with a first look at results from the final DES observing season.