8:20: SX
CalUnit is in
Hexapod set ack to December position: [4.98; 0.39; -0.61; 211; -100], and FLAO board to: [-73.8; -45.9; 45.0].
PBL with crane give us no telescope access for the whole morning.
14:00: back to SX
CalUnit. We try to measure LGSW
FoV using the scan with FLAO stages:
- setup everything
- close loop on LGSW only
- align FLAO board on on-axis source
- open LGSW loop and close on FLAO
- measure LGSW FoV moving FLAO stages
LGSW pupils are out, we update the default position for
CalUnit:
Pupil |
X |
Y |
Blue |
330 |
411 |
Yellow |
371 |
438 |
Red |
525 |
412 |
and we save a new pupil target: 20160308_213346
HEXA |
5.03 |
0.68 |
-0.75 |
115 |
-86 |
Board |
-74.6 |
-52.2 |
45.0 |
|
|
We always forgot that all the time you acquire the LGSs from the AARB GUI we must read the hexapod position on the TCS GUI and set it back, otherwise the
AdSec offload doesn't work!
Scan w/ board: 1" in 3 steps. It doesn't work! We need a movement pattern that minimizes the jumps.
So we turn back to the scan w/ hexapod. Range= +/-10" of Rx and Ry in 11 steps:
Then we switch off the Pockels cells and we repeat the same measurement:
It seems very bad, better to keep the PC on!
We move the hexapod to match the best center position for the Blue pupil: [+0.5; +4.0]" so hexapod Rx, Ry= [115.5; -84.5]. Then we try another scan with +/-5" and 3 steps, we also acquire snapshots:
TN |
AO Gain |
Res. WF [nm rms] |
AO rec |
DIMM ["] |
JCL |
PCL |
Notes |
20160308_230004 |
0.2,0.15,0.1 |
809.75 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [-5. -5.] |
20160308_230013 |
0.2,0.15,0.1 |
617.749 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [-5. 0.] |
20160308_230022 |
0.2,0.15,0.1 |
770.694 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [-5. 5.] |
20160308_230030 |
0.2,0.15,0.1 |
462.385 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [ 0. -5.] |
20160308_230037 |
0.2,0.15,0.1 |
425.589 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [ 0. 0.] |
20160308_230044 |
0.2,0.15,0.1 |
766.201 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [ 0. 5.] |
20160308_230053 |
0.2,0.15,0.1 |
496.058 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [ 5. -5.] |
20160308_230059 |
0.2,0.15,0.1 |
681.166 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [ 5. 0.] |
20160308_230107 |
0.2,0.15,0.1 |
442.056 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [ 5. 5.] |
But the result is too coarse, we try again with +/-5" and 11 steps:
TN |
AO Gain |
Res. WF [nm rms] |
AO rec |
DIMM ["] |
JCL |
PCL |
Notes |
20160308_230336 |
0.2,0.15,0.1 |
761.167 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [-5. -5.] |
20160308_230344 |
0.2,0.15,0.1 |
564.576 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [-5. -4.] |
20160308_230351 |
0.2,0.15,0.1 |
483.518 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [-5. -3.] |
20160308_230358 |
0.2,0.15,0.1 |
609.246 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [-5. -2.] |
20160308_230405 |
0.2,0.15,0.1 |
741.035 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [-5. -1.] |
20160308_230414 |
0.2,0.15,0.1 |
547.257 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [-5. 0.] |
20160308_230422 |
0.2,0.15,0.1 |
404.791 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [-5. 1.] |
20160308_230429 |
0.2,0.15,0.1 |
349.546 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [-5. 2.] |
20160308_230437 |
0.2,0.15,0.1 |
440.695 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [-5. 3.] |
20160308_230444 |
0.2,0.15,0.1 |
722.726 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [-5. 4.] |
20160308_230451 |
0.2,0.15,0.1 |
638.472 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [-5. 5.] |
20160308_230459 |
0.2,0.15,0.1 |
722.007 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [-4. -5.] |
20160308_230506 |
0.2,0.15,0.1 |
470.798 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [-4. -4.] |
20160308_230513 |
0.2,0.15,0.1 |
708.846 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [-4. -3.] |
20160308_230520 |
0.2,0.15,0.1 |
408.113 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [-4. -2.] |
20160308_230527 |
0.2,0.15,0.1 |
609.419 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [-4. -1.] |
20160308_230535 |
0.2,0.15,0.1 |
613.857 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [-4. 0.] |
20160308_230544 |
0.2,0.15,0.1 |
432.222 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [-4. 1.] |
20160308_230551 |
0.2,0.15,0.1 |
292.562 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [-4. 2.] |
20160308_230559 |
0.2,0.15,0.1 |
340.059 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [-4. 3.] |
20160308_230607 |
0.2,0.15,0.1 |
627.633 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [-4. 4.] |
20160308_230614 |
0.2,0.15,0.1 |
635.562 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [-4. 5.] |
20160308_230622 |
0.2,0.15,0.1 |
570.143 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [-3. -5.] |
20160308_230629 |
0.2,0.15,0.1 |
607.315 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [-3. -4.] |
20160308_230636 |
0.2,0.15,0.1 |
548.269 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [-3. -3.] |
20160308_230644 |
0.2,0.15,0.1 |
556.938 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [-3. -2.] |
20160308_230652 |
0.2,0.15,0.1 |
687.29 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [-3. -1.] |
20160308_230700 |
0.2,0.15,0.1 |
469.776 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [-3. 0.] |
20160308_230707 |
0.2,0.15,0.1 |
330.702 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [-3. 1.] |
20160308_230714 |
0.2,0.15,0.1 |
298.046 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [-3. 2.] |
20160308_230722 |
0.2,0.15,0.1 |
394.222 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [-3. 3.] |
20160308_230730 |
0.2,0.15,0.1 |
575.505 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [-3. 4.] |
20160308_230737 |
0.2,0.15,0.1 |
724.837 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [-3. 5.] |
20160308_230746 |
0.2,0.15,0.1 |
656.191 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [-2. -5.] |
20160308_230753 |
0.2,0.15,0.1 |
629.761 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [-2. -4.] |
20160308_230801 |
0.2,0.15,0.1 |
677.461 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [-2. -3.] |
20160308_230809 |
0.2,0.15,0.1 |
628.19 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [-2. -2.] |
20160308_230816 |
0.2,0.15,0.1 |
534.518 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [-2. -1.] |
20160308_230823 |
0.2,0.15,0.1 |
388.494 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [-2. 0.] |
20160308_230831 |
0.2,0.15,0.1 |
380.721 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [-2. 1.] |
20160308_230840 |
0.2,0.15,0.1 |
340.856 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [-2. 2.] |
20160308_230847 |
0.2,0.15,0.1 |
357.292 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [-2. 3.] |
20160308_230855 |
0.2,0.15,0.1 |
536.135 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [-2. 4.] |
20160308_230902 |
0.2,0.15,0.1 |
658.561 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [-2. 5.] |
20160308_230909 |
0.2,0.15,0.1 |
490.854 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [-1. -5.] |
20160308_230917 |
0.2,0.15,0.1 |
644.304 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [-1. -4.] |
20160308_230925 |
0.2,0.15,0.1 |
433.772 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [-1. -3.] |
20160308_230934 |
0.2,0.15,0.1 |
647.015 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [-1. -2.] |
20160308_230941 |
0.2,0.15,0.1 |
610.891 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [-1. -1.] |
20160308_230950 |
0.2,0.15,0.1 |
376.242 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [-1. 0.] |
20160308_230957 |
0.2,0.15,0.1 |
472.482 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [-1. 1.] |
20160308_231005 |
0.2,0.15,0.1 |
350.26 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [-1. 2.] |
20160308_231012 |
0.2,0.15,0.1 |
360.166 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [-1. 3.] |
20160308_231020 |
0.2,0.15,0.1 |
701.369 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [-1. 4.] |
20160308_231028 |
0.2,0.15,0.1 |
660.275 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [-1. 5.] |
20160308_231036 |
0.2,0.15,0.1 |
605.845 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [ 0. -5.] |
20160308_231043 |
0.2,0.15,0.1 |
435.998 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [ 0. -4.] |
20160308_231050 |
0.2,0.15,0.1 |
477.708 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [ 0. -3.] |
20160308_231058 |
0.2,0.15,0.1 |
607.215 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [ 0. -2.] |
20160308_231105 |
0.2,0.15,0.1 |
449.55 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [ 0. -1.] |
20160308_231112 |
0.2,0.15,0.1 |
477.949 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [ 0. 0.] |
20160308_231120 |
0.2,0.15,0.1 |
404.573 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [ 0. 1.] |
20160308_231129 |
0.2,0.15,0.1 |
355.01 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [ 0. 2.] |
20160308_231137 |
0.2,0.15,0.1 |
394.784 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [ 0. 3.] |
20160308_231146 |
0.2,0.15,0.1 |
759.599 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [ 0. 4.] |
20160308_231154 |
0.2,0.15,0.1 |
781.32 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [ 0. 5.] |
20160308_231202 |
0.2,0.15,0.1 |
398.357 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [ 1. -5.] |
20160308_231210 |
0.2,0.15,0.1 |
626.564 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [ 1. -4.] |
20160308_231218 |
0.2,0.15,0.1 |
618.488 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [ 1. -3.] |
20160308_231226 |
0.2,0.15,0.1 |
548.412 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [ 1. -2.] |
20160308_231233 |
0.2,0.15,0.1 |
477.143 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [ 1. -1.] |
20160308_231240 |
0.2,0.15,0.1 |
525.653 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [ 1. 0.] |
20160308_231248 |
0.2,0.15,0.1 |
399.332 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [ 1. 1.] |
20160308_231255 |
0.2,0.15,0.1 |
353.324 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [ 1. 2.] |
20160308_231303 |
0.2,0.15,0.1 |
424.46 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [ 1. 3.] |
20160308_231311 |
0.2,0.15,0.1 |
982.676 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [ 1. 4.] |
20160308_231319 |
0.2,0.15,0.1 |
785.566 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [ 1. 5.] |
20160308_231328 |
0.2,0.15,0.1 |
509.126 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [ 2. -5.] |
20160308_231336 |
0.2,0.15,0.1 |
573.721 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [ 2. -4.] |
20160308_231344 |
0.2,0.15,0.1 |
717.847 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [ 2. -3.] |
20160308_231351 |
0.2,0.15,0.1 |
484.439 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [ 2. -2.] |
20160308_231359 |
0.2,0.15,0.1 |
526.765 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [ 2. -1.] |
20160308_231408 |
0.2,0.15,0.1 |
515.643 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [ 2. 0.] |
20160308_231417 |
0.2,0.15,0.1 |
392.844 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [ 2. 1.] |
20160308_231425 |
0.2,0.15,0.1 |
392.217 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [ 2. 2.] |
20160308_231432 |
0.2,0.15,0.1 |
458.22 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [ 2. 3.] |
20160308_231440 |
0.2,0.15,0.1 |
693.92 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [ 2. 4.] |
20160308_231448 |
0.2,0.15,0.1 |
883.248 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [ 2. 5.] |
20160308_231457 |
0.2,0.15,0.1 |
326.814 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [ 3. -5.] |
20160308_231505 |
0.2,0.15,0.1 |
566.759 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [ 3. -4.] |
20160308_231513 |
0.2,0.15,0.1 |
502.968 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [ 3. -3.] |
20160308_231520 |
0.2,0.15,0.1 |
736.446 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [ 3. -2.] |
20160308_231528 |
0.2,0.15,0.1 |
489.705 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [ 3. -1.] |
20160308_231536 |
0.2,0.15,0.1 |
478.088 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [ 3. 0.] |
20160308_231543 |
0.2,0.15,0.1 |
447.954 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [ 3. 1.] |
20160308_231552 |
0.2,0.15,0.1 |
423.714 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [ 3. 2.] |
20160308_231600 |
0.2,0.15,0.1 |
572.601 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [ 3. 3.] |
20160308_231607 |
0.2,0.15,0.1 |
885.852 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [ 3. 4.] |
20160308_231615 |
0.2,0.15,0.1 |
756.345 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [ 3. 5.] |
20160308_231622 |
0.2,0.15,0.1 |
254.006 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [ 4. -5.] |
20160308_231631 |
0.2,0.15,0.1 |
493.237 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [ 4. -4.] |
20160308_231638 |
0.2,0.15,0.1 |
527.481 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [ 4. -3.] |
20160308_231645 |
0.2,0.15,0.1 |
632.203 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [ 4. -2.] |
20160308_231652 |
0.2,0.15,0.1 |
621.532 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [ 4. -1.] |
20160308_231700 |
0.2,0.15,0.1 |
497.812 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [ 4. 0.] |
20160308_231707 |
0.2,0.15,0.1 |
440.883 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [ 4. 1.] |
20160308_231715 |
0.2,0.15,0.1 |
488.994 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [ 4. 2.] |
20160308_231723 |
0.2,0.15,0.1 |
734.599 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [ 4. 3.] |
20160308_231731 |
0.2,0.15,0.1 |
945.47 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [ 4. 4.] |
20160308_231739 |
0.2,0.15,0.1 |
831.74 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [ 4. 5.] |
20160308_231747 |
0.2,0.15,0.1 |
465.971 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [ 5. -5.] |
20160308_231755 |
0.2,0.15,0.1 |
442.95 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [ 5. -4.] |
20160308_231802 |
0.2,0.15,0.1 |
485.232 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [ 5. -3.] |
20160308_231811 |
0.2,0.15,0.1 |
587.039 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [ 5. -2.] |
20160308_231818 |
0.2,0.15,0.1 |
706.088 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [ 5. -1.] |
20160308_231826 |
0.2,0.15,0.1 |
585.077 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [ 5. 0.] |
20160308_231833 |
0.2,0.15,0.1 |
641.572 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [ 5. 1.] |
20160308_231841 |
0.2,0.15,0.1 |
590.365 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [ 5. 2.] |
20160308_231849 |
0.2,0.15,0.1 |
545.292 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [ 5. 3.] |
20160308_231857 |
0.2,0.15,0.1 |
757.963 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [ 5. 4.] |
20160308_231905 |
0.2,0.15,0.1 |
618.045 |
20151212_220700 |
-1 |
F |
F |
Lgsw Fov hexa [ 5. 5.] |
We are more convinced that the best center for the
FoV is guessed from the larger scan (>10"). So we put the hexapod in the position that matches the 3
FoV centers and we close the jitter loop (having init position = 'zero') to measure the init positions:
Pupil |
[Rx; Ry] |
PI |
Blue |
[115.0; -88.5] |
[-1.25; 3.15] |
Yellow |
[112.5; -88.3] |
[-2.20; 0.40] |
Red |
[110.5; -88.5] |
[-4.50; 0.40] |
These values are saved in a new
jitter initial position: 20160309_000200
then we try another scan from [115.0; -88.5] with +/-10" and 11 steps keeping the jitter loop closed. BAD IDEA! when the spot is out of the
FoV the piezos go banana and never get back!
Last scan with +/-20" and 11 steps: