This is cheap spectrometer or $9. The slit I think is a little too wide. Unfortunately scale is not readable with my vision. Fortunately, seems feasible to take photos and it’s a bit more readable. Photo above is with my old iPad. Lemme try new iPhone.
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iphone proved impossible. Will have to improvise some sort of fixture for it. Webcam on desk monitor seems more promising. Not sure why I'm getting reflection artifacts. I think interior of the thing isn't nonreflective enough perhaps.
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Getting some diffraction gratings soon. Might try to make my own.
Interesting question… those numbers *say* 4, 5, 6, 7… supposedly 100s of nanometers, but how do I know? What if the experts have been lying to me all along? What if there’s a conspiracy to rig the scale?
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I could calibrate the yellow sodium line with a candle and some salt on a needle, but again I have to take their 3rd for it. Only way is to check the derivation from the grating geometry and measure the grating line spacing myself… supposedly 13.5k lines per inch.
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I vaguely recall learning the operating principles of diffraction in high school. Some shit about waves and angles. But tbh I’ve completely forgotten it. Need to brush up.
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Shits getting serious here
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Optics starter kit. Concave and convex mirrors and lenses, a prism. Can’t find a cheap decent collimated light source. Might have to make one
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Really weird that I can’t find a good broad spectrum light source at home. All my lamps are CFLs or LEDs, and my workshop also has only LEDs. Gonna have to actually find a small incandescent lightbulb somewhere. These things might soon be hard to find.
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Wonder if there are health consequences of spending so much time in narrowband environments.
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Made a lens holder. Idea is to run it on an aluminum square tube to make an optical bench but I got the tolerance of square hole wrong so it doesn’t fit. Lens sits nicely though
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Saw in 2/3 of the way along the vertical from one side & 2/3 along the horizontal from the other side, cf. this type of collet except far simpler:
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Already tried something like that. Problem is the vertical dimension is also off
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That’s sawing all the way through one wall from the bottom
My suggestion was sawing 2/3 through top and bottom walls from the front, and 2/3 through the side walls from the back, sort of like the parts I showed but fewer cuts than that of course
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hmm... will try that next time, but am reprinting with other modifications and increased tolerances anyway
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