I think real radiation emitting bodies has an emissivity smaller than one as they are not pure black body radiator. Therefore you may not be able to get the temperature by full curve fitting. Rather you can locate the position of the maximum wavelength, it is also related to temperature and from which you can get the temperature of the body.

For this relationship please refer to the link: metrology.tkk.fi/courses/S-108.4010/2006/tempmeas.ppt

Best wishes

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in addition to the above, sse the section "Peaks" below (and beware of the different "BBR curves" !)

https://en.wikipedia.org/wiki/Planck%27s_law

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Hi Dalim,

I don't know exactly what model you used to fit the data. This attached curvefit is just an attempt to fit your data with a scaled Planck's law:

Bλ(λ, T) = a*((2*(h)*(c)^2)/((λ)^5))*(1/(exp(((h)*(c))/((λ)*(k)*(T))) − 1))

where

a = scaling coefficient

h = 6.62607004 × 10−34 J⋅s

c = 299792458 m/s

k = 1.38064852 × 10−23 J⋅K−1

Thank you Dr. Zekry, Chak, and Clerot for sharing your thoughts.