/tmp/output_frames/frame_0001.png
2080    # idim_site
2080    # jdim_site
1050    # ricen_site  
1093    # rjcen_site  (increases from bottom to top in the image)
950.    # radius_site (lower number enlarges horizon image scale)
0.      # rotate_z    ! legacy
90.     # altitude    ! Y rotation (altitude of lens axis relative to airframe or camera mounting)
183.5   # azimuth     ! X rotation (azimuth of lens axis - lower edge of image if at the zenith)  
0.      # rot_cam     ! Z rotation (positive number shifts [counter]-clockwise)
0.,0.,0. # roll_angle
1.      # a
-0.01   # b           (larger b increases zenith image scale) [-0.12,=0.06]
-0.05   # c           (larger c lowers the low altitudes)
1.00    # ecc2  
90.     # angular radius polar
90.     # pole_alt (altitude of nominal polar input/output images (zenith or nadir, +/-90. degrees respectively)
0.25    # azi_scale
999.    # azi_hw
0.0,1.00,1.00,1.00 ! vignet_exp, RGB stretch (larger vignet, larger stretch is brighter)