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Question:orientation of slit vs that of diffraction grating

wlkwong is asking a question about spectrometer: Subscribe to answer questions on this topic

wlkwong asked on January 01, 2017 09:30
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What I want to do or know

I am constructing (reconstructing) the mini-spectrometer. I would like to know if the slit on the front end should lie in the same direction of the diffraction grating, i.e. if the "grating is vertical, making a horizontal spectral rainbow" - as mentioned under #2 of the instruction sheet; then the slit should also be vertical? (but in the diagrams of #3, the slit is drawn horizontal.

Thank you for any advice. wlkwong

Background story

question:spectrometer question:spectral-workbench question:foldable-mini-spectrometer


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2 Answers

Hi @wlkwong!
I've built my personal mini spectrometer using a 1" PVC tube. The collimation slit is attached to a 1" cap so I can pull it out and rotate the orientation of the slit. Here are two pictures of the same source of light reflected on a white surface. The first one has the slit as the foldable mini spectrometer. For the second one I've rotated the collimation slit 90 degrees.
I'm not an expert so I leave the analysis to the senior spectrometer fellas ;)

ps: Sorry but trying to change the picture, now I'm having troubles with the uploader. Find the PICTURE HERE https://pbs.twimg.com/media/C1QP2VgWIAEPEKC.jpg:large

Indeed I think it's possible to answer this empirically - for example in @xose's, horizontal is the correct orientation.

It's hard to describe verbally, but the slit should be parallel to the track lines on the DVD -- tangent to them, that is, to be a bit more precise.

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