The most technical part of the experiment is bending the mirror in such a way that the reflected light hits the screen. One should start by directing the spectrum reflected from a flat mirror onto the screen. Once this reflection is found, we can begin to carefully bend the mirror, while observing how the reflected spectrum becomes narrower. Eventually it becomes a white line.

To bend the mirror, attach larger paper clips to its ends and bend only by holding them. This ensures a situation where the bending of the mirror shape is close enough to the circle shape. If the white stripe has colored edges, then we need to adjust the way we bend the mirror.