Catch a star

An aperture of f/13 or narrower turns bare light bulbs and street lights into so-called starbursts. Depending on the type of lens and size of the aperture you’ll get different shaped starbursts, but it’s best not to go above f/16 as the lens will start to introduce diffraction, which softens the whole image. It’s a trade-off between sharp images on the one hand, and brilliant lights on the other.