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View Full Version here: : Wavelength calbration jig for slitless spectrometer (with SA100)


bojan
29-03-2025, 12:09 PM
In order to make wavelength calibration easier and more accurate (especially when there are no prominent spectral lines in the spectrum), I put together this gadget.
It is assembled with already made parts from my other projects (like SHG, which is still in pipeline), old 50mm lens (Domiplan 2.8). So instead of slit, I used aluminized optical fiber, illuminated with neon lamp (mains indicator), but of course other light sources can be used.
The results look promising, but something seem to be wrong with my polynomial interpolation of wavelength points (BASS app).. I am not sure why the calibration is shifted in the middle, while entering wavelengths, all looked OK (I used 4-polymomial interpolation).. I asked for help in GroupsIO, maybe someone will know what I am doing wrong.
This experiment was done with Tair-11A+Canon 450D (modded), now I have to try it on C11....

bojan
09-06-2025, 05:21 PM
The reason for the problem with calibration was the erroneous annotation in the Neon spectrum image, which I posted in previous post.

I found it couple of days later and already notified the author of the image, and then I forgot about this post, sorry.



So here are the corrected spectrum images from previous post.