Assuming the Ronchi and the Hartmann tests to be null tests, we were able to design special screens for each test that produce aligned straight fringes and a square array for the observed patterns. It also became clear that the screen filter and observing planes for both tests can be interchanged.
© 1990 Optical Society of America
Alberto Cordero-Davila, Alejandro Cornejo-Rodriguez, and Octavio Cardona-Nunez, "Null Hartmann and Ronchi-Hartmann tests," Appl. Opt. 29, 4618-4621 (1990)