Above is an image scanned in from my textbook of an interefernce pattern from two slits. Am I correct in thinking that the distance between the maxima within the main envelope is found via λ = ws/D , where w = this distance? Also, would the minima of the main envelope be found using dsin(theta)= nλ? How would should a pattern physically be seen? Would the brighter regions have a series of darker regions within them? Thanks!