Flatness testing box?

[legswilly]

I am interested in testing optical flatness. I did come across a method that used what looks like a red light (monochromatic?) and a plastic diffuser. The globes looked like the energy saver type, but with a red glow. The box had a pane of glass at a 45deg angle. The piece to be tested was at the bottom of the box.
I wish I had it bookmarked. Has anyone seen the clip? Please give me a link to it?

[Atmos]

From memory it was a document provided by Starlight Xpress (https://www.sxccd.com) but I cannot remember any other details.

[legswilly]

Thank you for the link. I have contacted them and hope I get an answer.

[legswilly]

I contacted them and they said it is not one of their articles, but they gave me a link https://www.grattavetro.it/interferometro-di-newton/?lang=en and that shows the same test rig, bar the light source. I will be able to scale this to what I need.


Thank you Colin