Quote:
Originally Posted by DavidU
Thanks Mark ! Is a ball bearing still the go during sunny days?
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A ball is certainly easier than building an illuminated pinhole.
Monochromatic light from a suitable LED will give clearer fresnel ring structure for collimating.
The distance of the source determines how much residual spherical aberration will be inherent in the test set up. The size of the source will determine whether or not you can observe any genuine Airy pattern structure or not, and is really only important if you want to study the optics for finer defects rather than just collimate it.