I have a question about a limiting angle of resolution when viewed from a circular aperture. I'm trying to find the distance between two lights of a certain wavelength. The lights appear to merge into one at a given distance when viewed through an aperture of some given size. So far I've tried these equations: theta(min)=1.22(lambda/D) I know both lambda and D (diameter), so I now know theta(min). Now I've tried theta(min)=d/L where I know L(distance at which the lights appear to merge) but not d. After solving for d I still can't get the right answer. If anyone could help me out a it'd be great. Thanks a lot.