At this point you can move to a knife edge , which will allow you to refocus the apparent shape to pick the best work line to work towards a plane wavefont in the null , which is not really a strategy available with a ronchi grating , which just displays the progression of relative slopes from centre to edge .
Quote:
Originally Posted by Stefan Buda
Thanks Rod!
The Ross Null test is just about as useful as the Ronchi test would be if the mirror was spherical. In other words, it becomes difficult to interpret when you approach the required precision of better than 1/4 wave.
|