Dispersion and refractive index chart

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skywxp3d
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Posts: 42
Joined: Mon Jun 11, 2012 9:23 pm
Location: Seattle

Hey all, I just found this chart - it has liquids and glass - hey can you tell me if the "Chromatic dispersion" number on this database is the same # used in the Cauchy based "Dispersion" input in Octane? Im thinking it is but not tottaly sure... If so - this could be extremely helpfull!!


http://refractiveindex.info/?group=HOYA&material=BSC7
Sky Kensok
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t_3
Posts: 2871
Joined: Tue Jul 05, 2011 5:37 pm

great find; only the chromatic dispersion is _not_ the cauchy b coefficient; but you can calculate it from the abbe number, it's formula c & f wavelengths and the refractive index...

B = ( nd - 1 ) / Vd * ( ( F² * C² ) / ( C² - F² ) )

or in terms taken from the link you posted:

B = ( 1.5168 - 1 ) / 64.2 * ( ( 0.48613² * 0.65627² ) / ( 0.65627² - 0.48613² ) ) = 0.00421534

basics for the transformation:
http://www2.ph.ed.ac.uk/~wjh/teaching/o ... ersion.pdf
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