BirdForum is the net's largest birding community dedicated to wild birds and birding, and is absolutely FREE!

Register for an account to take part in lively discussions in the forum, post your pictures in the gallery and more.

Reply to thread

Message: <blockquote data-quote="Kevin Purcell" data-source="post: 1310733" data-attributes="member: 68323">I've looked at enough diffraction images (and done enough of the theory) to be able to interpret them. Trust me. I know the direction of the diffracting edge and which direction has reduced resolution.The two set of star tests are identical (they point to the same jpegs ... if you check the image links) so there is no ambiguity. He's explaining the same issue with two images. The first showing how s- and p- interference degrades the star image. The second showing a corrected image in both cases.Again he could be more concise and more clear but from the context it's pretty clear. This is why we use phase-corrected roof prisms to improve resolution and contrast in the direction at right angles to the roof edge.Now back to the spikes ... if you have a roof prism bin try the experiment and add your result to the thread.</blockquote>