Talk:Null corrector

First diagram can't be correct

The first diagram can't be correct.

To get an interferogram off to the left, you need both the beam from the mirror being tested and a reference beam from the laser to interfere with it. The beam from the laser should go off to the left at the beam splitter...but it's not illustrated in the diagram. Furthermore, it's diverging at that point, so some optics would be required to send it back at the same angle as it leaves the beam splitter. This means at very least optics to collimate the light and a mirror to reflect it back along the same path it left so that it can then go through the beam splitter off to the right and interfere with the light from the mirror being tested. I suppose a spherical mirror could combine the collimation and reflection.

However, none of this is illustrated in the diagram.

Bill Jefferys (talk) 23:43, 23 October 2015 (UTC)