A simple Michelson interferometer is generally presented like the one bellow
Is it the lens of the telescope that form theses fringes? Because if we use a monochromatic light source, say a laser, the result we are supposed to see is simply a spot that would be bright or dim depending on the kind of interference, not fringes. So is there some other optical equipment between the final beam and the telescope? Or is it just the lens of the telescope that causes these fringes, as opposed to a spot, to appear?