In sci.astro.amateur message ,
Fri, 31 Dec 2010 13:05:43, N_Cook posted:


An umbrella and nightime streetlamp is inexpensive for diffraction pattern.


Try some equivalent of an old-fashioned metal foil milk-bottle top,
pierced with the smallest closest holes you can do by hand with a fine
sewing needle, then using the foil as a monocle to inspect a distant LP
sodium lamp. The effect is not as pretty as from a CD, but it's
definitely there. The millimetre scale of a plastic ruler, at grazing
incidence, will also show an effect.

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