Collimation and 4.0-m lookup tables

  • Shapzz.help: instructions to reduce Hartmann data with Shap
  • In the following, all the wavefront aberration amplitudes mentionned for Zemax simulations are representing true Zernike polynomials, and the ones measured with the telescope are just similar, although called quasi-Zernikes.
  • Latest astigmatism lookup table at f/8 (3-4 Feb 01); sky map at f/14 showed same aberrations thus the problem is likely to be bound to M1 and the lookup table is used at all foci.
  • Latest trefoil lookup table at f/8 (3-4 Feb 01): constant vector (0.25um, 349deg); no aberration pattern seen at f/14 thus the problem is bound to the f/8 M2.
  • Latest quadrafoil lookup table at f/8 (3-4 Feb 01): constant vector (0.17um, 191deg); sky map at f/14 showed same aberrations thus the problem is likely to be bound to M1 and the lookup table is used at all foci.
  • SCALE OF THE WAVEFRONT ERRORS (optical path difference at the edge of the pupil): at the 4m, 0.1" image degradation is produced by 0.70um of coma, 0.30um of astigmatism, 0.26um of trefoil, 0.24um of quadrafoil.
  • Records of old lookup tables can be foun in  /ut02/4map