We use survey telescopes to look for asteroids. Typically they have been much smaller than the research telescopes. This is about to change with the Rubin Observatory which has an 8 meter mirror, putting into the research size range.

This telescope has a 3200 megapixel camera, and a wide field of view. It will survey the sky frequently, looking for anything that changes (moving asteroids and comets, variable stars, planetary transits, etc.)