Convert fwhm_geom to fwhm_eff. This conversion was calculated by Bo Xin and Zeljko Ivezic (and will be in an update on the LSE-40 and overview papers).
- fwhm_geom: `float`
The geometric FWHM value, as measured from a typical PSF profile, in arcseconds.
FWHM effective, the single-gaussian equivalent FWHM value, appropriate for calc_neff, in arcseconds.