Bob Higgins <rj.bob.higg...@gmail.com> wrote:
> Because of the porosity of the alumina, the ceramic is a reddening (low > pass) filter, so the light from the much hotter internal heater coils will > be reddened as it is transmitted. . . . > Ryan had a follow-up comment along those lines: "The color they glow at varies a bit with emissivity. In the case of the dogbone, there appears to be controversy over whether it is transparent in the range of the heating element so the optris thermal camera might have measured the element temperature." - Jed
