White Light Fringes

Part 3 of the Michelson lab, where we examine interference fringes from an incandescent lamp. The lamp emits a full spectrum, so there are many different wavelengths of light in the interferometer. If the two interferometer arms are EXACTLY the same length, the recombined beams should constructively interfere for ALL the different wavelengths present, but that can only be true at one position for the traveling mirror. And what if the wavefronts or the optics are not perfectly flat, as is certainly true for our setup?