Preliminary procedure:

1. for any elevation, capture an image with the 4D interferometer
2. save the data including: img, mask, elevation
3. compute a zernike fit (surf_fit[1,2,3,4,5,6], zcoeff=zz) & zern5=zz[4]
4. iterate untile a full measurements cycle is completed
5. save zern5, elev in a file in meas/astig/tracknum/astig_lut.sav
6. copy the file in calib/...../data/astig_lut.sav

• elev (elevation, degrees, double)
• zern5 (zernike term 5 =Z5, m RMS over the pupil, WaveFront as measured by the interferometer and RRoptics, wedge=0.5)