General description: This file contains the flux distortion image.
Naming convention: spFluxdistort-pppp-mmmmm.fits, where pppp is the plate number and mmmmm is the MJD.
Approximate size: 18 MB.
File type: FITS
Read by products: spec2d
Written by products: spec2d (spcoadd_v5.pro)
Image with the flux distortion vector for each fiber.