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Message: <blockquote data-quote="Surveyor" data-source="post: 1289601" data-attributes="member: 50720">Henry, Thanks for the input Henry. I found a couple of tricks while playing with the star test over the last couple of months. First the apparent filtering seems to work well and is just done by selecting different colored Christmas ornaments, I keep a green, red, blue, yellow and silver ball on the table, size 60mm. Also use two size ball bearings, 25 and 12 mm. I use a modified method of the glitter point by using an aperture along with it. I made up a spread sheet using Suitors math in the appendix of his book to adjust the aperture to whatever size I want and also lets me set two apertures a known distance apart for scaling purposes. I attached a jpg of the spread sheet set up for this test. I learned a lot from trying to photo this and have a few ideas I am going to try over the next couple of weeks. I too was surprised by the transmission curve but feel fairly confident, within the limitations of my very cheap equipment. You will notice that I showed two curves for one of the tubes. I was concerned about my setup and actually made 3 runs of the right tube. I completely redid the second run with the same parameters as the first, That did not make me feel any better so I tore the whole setup down and changed from a 10mm collimated beam to a 5 mm collimated beam and that is the result shown as #2 on the chart. I expected lower but using 0.7% loss and 8 elements would bring me down to 94.4% and measured about 91.?% (peak) average so that would leave about 3% in the prism, maybe a realistic possibility. Thanks again for your input.Ron</blockquote>

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