This is the output from imwcs run in verbose mode (-v):
$ > imwcs -vwi 5000 testx90m.fit
testx90m.fit:
RA=16:15:51.147 DEC=+31:23:36.44 W=1024 H=1024 ArcSecs/Pixel=0.651364
1 region: 13 / 3098 found
using all 13 reference stars
GSC:
2580.2232 16:15:57.372 +31:18:38.56 12.39 389.6 55.1
2580.1696 16:15:49.339 +31:26:42.40 13.38 547.5 797.2
2580.1207 16:15:45.511 +31:27:48.64 13.50 622.6 898.8
2580.2291 16:16:08.345 +31:26:15.76 13.81 174.4 756.5
2580.1629 16:15:55.896 +31:19:58.40 13.91 418.7 177.6
2580.1158 16:16:12.139 +31:28:54.01 13.99 100.1 999.2
2580.1710 16:15:56.083 +31:24:24.44 14.13 415.1 585.6
2580.1798 16:15:34.867 +31:24:43.45 14.16 831.6 614.9
2580.1909 16:15:37.282 +31:23:51.97 14.76 784.3 535.9
2580.1943 16:15:41.477 +31:26:37.54 14.84 701.8 789.8
2580.1485 16:15:52.958 +31:25:15.56 14.88 476.4 664.0
2580.1667 16:15:37.757 +31:19:16.68 14.91 775.2 113.7
2580.1878 16:16:10.956 +31:21:42.41 14.92 122.9 337.2
using brightest 13 / 13 reference stars
using brightest 13 / 16 image stars
Im: 737.1 763.5 132652.0 32145
Im: 209.4 861.3 114094.6 29360
Im: 661.3 661.0 113744.0 32061
Im: 528.5 33.5 101758.2 32342
Im: 960.5 978.4 70186.9 32694
Im: 947.9 475.8 64678.8 32496
Im: 817.0 653.4 54077.0 16566
Im: 283.5 620.5 51179.8 32111
Im: 899.7 396.1 39752.0 17609
Im: 229.8 196.1 34583.6 14863
Im: 30.2 921.7 33853.8 13624
Im: 986.0 507.2 28483.2 9859
Im: 588.8 526.6 25958.9 15763
0: 16:15:56.823 +31:25:06.62 rot=-0.076 del=-0.6451 -0.6451 y=21.5855
1: 16:15:56.823 +31:25:06.62 rot=-0.076 del=-0.6451 -0.6451 y=21.5855
2: 16:15:56.823 +31:25:06.62 rot=-0.076 del=-0.6451 -0.6451 y=21.5855
3: 16:15:56.823 +31:25:06.62 rot=-0.076 del=-0.6451 -0.6451 y=21.5855
4: 16:15:56.823 +31:25:06.62 rot=-0.076 del=-0.6451 -0.6451 y=21.5855
iter=282
cra= 16:15:56.823 cdec= +31:25:06.62 rot=-0.0761 del=-0.6451 -0.6451
1: X: g 16:16:10.956 s' 16:16:11.039 e: 1.2389
Y: g: +31:21:42.41 s': +31:21:42.79 e: 0.38 r= 1.30
2: X: g 16:15:49.339 s' 16:15:49.298 e: -0.6233
Y: g: +31:26:42.40 s': +31:26:42.74 e: 0.35 r= 0.71
3: X: g 16:15:45.511 s' 16:15:45.473 e: -0.5744
Y: g: +31:27:48.64 s': +31:27:48.81 e: 0.18 r= 0.60
4: X: g 16:16:08.345 s' 16:16:08.341 e: -0.0633
Y: g: +31:26:15.76 s': +31:26:16.59 e: 0.83 r= 0.83
5: X: g 16:15:55.896 s' 16:15:55.992 e: 1.4384
Y: g: +31:19:58.40 s': +31:19:57.92 e: -0.48 r= 1.52
6: X: g 16:16:12.139 s' 16:16:12.082 e: -0.8523
Y: g: +31:28:54.01 s': +31:28:51.90 e: -2.11 r= 2.28
7: X: g 16:15:34.867 s' 16:15:34.858 e: -0.1433
Y: g: +31:24:43.45 s': +31:24:43.14 e: -0.31 r= 0.34
8: X: g 16:15:37.282 s' 16:15:37.289 e: 0.1092
Y: g: +31:23:51.97 s': +31:23:51.77 e: -0.20 r= 0.23
9: X: g 16:15:41.477 s' 16:15:41.445 e: -0.4708
Y: g: +31:26:37.54 s': +31:26:37.76 e: 0.23 r= 0.52
10: X: g 16:15:52.958 s' 16:15:52.950 e: -0.1309
Y: g: +31:25:15.56 s': +31:25:16.03 e: 0.46 r= 0.48
10 bin hits
Rotation: -0.0761369 degrees Arcsec/pixel: -0.645123 0.645123
New center: 16:15:56.823 +31:25:06.62 (FK5)
New center: 16:13:59.719 +31:32:29.80 (FK4)
Matches in GSC:
2580.1696 16:15:49.339 +31:26:42.40 13.38 661.3 661.0 32061 0.97 0.64
2580.1207 16:15:45.511 +31:27:48.64 13.50 737.1 763.5 32145 0.71 0.52
2580.2291 16:16:08.345 +31:26:15.76 13.81 283.5 620.5 32111 0.98 0.83
2580.1629 16:15:55.896 +31:19:58.40 13.91 528.5 33.5 32342 1.46 1.32
2580.1158 16:16:12.139 +31:28:54.01 13.99 209.4 861.3 29360 3.73 2.23
2580.1798 16:15:34.867 +31:24:43.45 14.16 947.9 475.8 32496 0.26 0.33
2580.1909 16:15:37.282 +31:23:51.97 14.76 899.7 396.1 17609 0.21 0.22
2580.1943 16:15:41.477 +31:26:37.54 14.84 817.0 653.4 16566 0.87 0.46
2580.1485 16:15:52.958 +31:25:15.56 14.88 588.8 526.6 15763 0.83 0.48
2580.1878 16:16:10.956 +31:21:42.41 14.92 229.8 196.1 14863 1.24 1.12
Mean dx= 0.00 dy= 0.00 dxy= 1.13 sep= 0.82
Writing testx90mw.fit
[WCS programs]
[IMWCS]