Quote:
Originally Posted by DavidU
Any ideas on making a 100 micron hole? I was going to enquire about the sizes of acupuncture needles?
cheers
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Fold up a piece of foil until you have many layers. Sharpen up a needle on a grinding stone until you have a really fine tip. Stab the wad of foil, but not right through, and then unravel it until you can find the smallest hole. It's not hard to make a 50 micron pinhole this way.
The smaller the hole , the better definition you'll see in the light and dark Fresnel rings you see when you defocus a star, which will allow you to collimate to a better accuracy.