Quote:
Originally Posted by darkman
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Depending of observing spectrum it is not unimportant how many lines per mm has our diffraction grating.
Observing whole spectrum, as on video above, best compromise is about 500-600 lines per mm:
https://wasatchphotonics.com/product...UaArXuEALw_wcB
So for observing the whole light spectrum it is better to use CD as diffraction grating, than DVD/R.
But DVD/R can be more suitable, if we are interested in specific part of light spectrum (par example IR
and trans IR), according this data:
"On a CD the track pitch is 1.6 microns or 625 lines per mm. A 3.95GB DVD-R has a track pitch of
0.8 microns or 1,250 lines per mm. A 4.7GB DVD-R has a track pitch of 0.74 microns or 1,351 lines
per mm. So a DVD-R acts as a diffraction grating with 1,351 lines per mm and a CD-R would have
about half that."