Removal of HgAr continuum in focus and defocus

Contamination of the HgAr data with the continuum remains the problem. The reduction pipeline has algorithm that should remove this effect.
This is to 1. Estimate the quality of this subtraction - if good enough use this for focused images
2. Use the insights (i.e., the function form of the continuum as a function of wavelength) to subtract the defocused images, as well.