MeerK40t calibration scan report - s1 - 2026-10-31 22:13:20 CDT
burned with: lens_size 131.5 mm, flip_x False, flip_y True, swap_xy True, rotate 0, cor ref/jcz110.cor
scan: snipped corner found at scan BR; rotating scan 180 deg CCW so it is top-left; marks LIGHTER than paper; 1464 points; pips 12/12

ORIENTATION: burn appears correct (not mirrored, not rotated)
  -> no flip/swap change needed
SCALE: X +1.055 %   Y +2.003 %   mean +1.527 %  (+ = burn too big)
  centre-line rulers X +0.898 %  Y +1.807 % ;  square edges X +1.313 %  Y +2.324 %
  -> MeerK40t Lens Size: 131.5 -> 133.509 mm   (only global-scale knob MeerK40t has)
SKEW: +0.2292 deg (angle between burned X and Y axes minus 90)
TRAPEZOID: top-bottom -0.483 %   left-right -0.604 %
  outer square sides (nominal 100, rotation removed): top 101.068 bottom 101.558 left 102.015 right 102.633
BOW of outer sides (mm, + outward = barrel, - inward = pincushion): {'top': -0.26, 'right': -0.31, 'bottom': -0.257, 'left': -0.104}
CENTRE: cross is [-0.103, 0.052] mm (x,y) from the outer-square centre
CIRCLE circle_big: nominal 70.0 -> 71.335 x 70.64 mm (ovality 0.695 at 12.1 deg)
CIRCLE circle_centre: nominal 15.0 -> 15.276 x 15.129 mm (ovality 0.147 at 12.1 deg)
CIRCLE circle_corner_BL: nominal 8.0 -> 8.184 x 8.067 mm (ovality 0.117 at 40.0 deg)
CIRCLE circle_corner_BR: nominal 8.0 -> 8.234 x 8.061 mm (ovality 0.173 at 147.0 deg)
CIRCLE circle_corner_TL: nominal 8.0 -> 8.168 x 8.078 mm (ovality 0.089 at 175.9 deg)
CIRCLE circle_corner_TR: nominal 8.0 -> 8.257 x 8.029 mm (ovality 0.229 at 28.1 deg)
RULER tick errors after best similarity fit (mm): {'x-44': 0.249, 'y-44': -0.128, 'x-30': 0.156, 'y-30': -0.068, 'x-20': 0.08, 'y-20': -0.032, 'x-10': 0.047, 'y-10': 0.005, 'x+10': -0.11, 'y+10': 0.05, 'x+20': -0.14, 'y+20': 0.09, 'x+30': -0.219, 'y+30': 0.101, 'x+44': -0.297, 'y+44': 0.12}
MARK STRENGTH by region (weak-corner check): {'TL': 90.2, 'TR': 89.8, 'BL': 90.2, 'BR': 90.2, 'centre': 90.3}
FIT RMS (mm): {'rigid': 0.6111, 'similarity': 0.207, 'affine': 0.0896, 'cubic': 0.0099}
WORST POINT (mm, inside the 100 mm square): rigid-only 1.612 ; after lens fix only 0.691
NEW .cor: /tmp/mkcal_selftest/s1_corrected_L133.509.cor  (max table change 366.7 ticks, gain 1.00, sign +1)
  half-strength alternative: /tmp/mkcal_selftest/s1_corrected_L133.509_half.cor
  after selecting this .cor in MeerK40t the GUI resets Lens Size to 125.002 - type 133.509mm back in