1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
|
#******************************************************************************
# E.S.O. - VLT project
#
# "@(#) $Id: ESO-DFS-DIC.FORS2_QC,v 1.17 2011-10-05 16:03:34 cgarcia Exp $"
#
# $Name: not supported by cvs2svn $
# $Revision: 1.17 $
# $Log: not supported by cvs2svn $
# Revision 1.16 2011/04/01 14:43:06 cizzo
# Complete add QC.NANGLES
#
# Revision 1.15 2011/04/01 14:34:34 cizzo
# Add QC.NANGLES
#
# Revision 1.14 2010/04/27 12:10:46 cizzo
# Fix incorrect one line doc
#
# Revision 1.13 2010/04/26 11:41:29 cizzo
# Add definition of standard stars related QC parameters for PMOS
#
# Revision 1.12 2010/02/10 16:00:11 cizzo
# Add QCs for spectral efficiency monitoring
#
# Revision 1.11 2009/05/04 10:07:09 cizzo
# Add new QC, QC.PMOS.CENTRAL.WAVELENGTH
#
# Revision 1.10 2009/03/31 10:49:22 cizzo
# Add SKYFLAT FLUX MIN/MAX
#
# Revision 1.9 2009/02/01 14:26:29 cizzo
# Add new parameters QC TRACE MAX CURVATURE and QC TRACE MAX SLOPE
#
# Revision 1.8 2008/08/18 14:27:45 cizzo
# Rename QC from QC.WAVE.MEAN.ACCURACY to QC.WAVE.ACCURACY, and add new QC QC.WAVE.ACCURACY.ERROR
#
# Revision 1.7 2008/07/31 09:12:13 cizzo
# Add several new QCs related to atmospheric extinction and wavelength calibration accuracy
#
# Revision 1.6 2008/03/14 10:30:57 cizzo
# Add QC FLAT FPN REL
#
# Revision 1.5 2008/01/29 13:33:38 cizzo
# Add QC.EXTCOEFFERR
#
# Revision 1.4 2007/11/19 15:09:23 jmlarsen
# Added QC.MBIAS.LEVEL
#
# Revision 1.6 2007/11/02 12:42:56 jmlarsen
# Removed fixme comments
#
# Revision 1.5 2007/10/30 14:45:02 jmlarsen
# Added QC.EXTCOEFF
#
# Revision 1.4 2007/10/19 11:55:23 jmlarsen
# Updated descriptions of QC.SKYRMS, QC.IMGQU, QC.IMGQUELL, QC.ZPOINT, QC.FLAT.CONAD, QC.FLAT.CONADERR. Added QC.IMGQUELLERR
#
# Revision 1.3 2007/10/18 14:38:13 cizzo
# Draft of new list of QCs
#
# Revision 1.2 2007/10/04 14:30:09 cizzo
# Imaging QC1 parameters entirely revised
#
# Revision 1.1 2007/09/14 11:29:48 cizzo
# Copied here from the old fspil module
#
# Revision 1.8.6.9 2007/03/02 15:22:21 cizzo
# No comment
#
# Revision 1.8.6.8 2007/02/06 08:19:29 cizzo
# Improve documentation of OUT1.EFF and FLAT.EFF
#
# Revision 1.8.6.7 2006/10/10 09:36:51 cizzo
# Add QC XXX RESOLUTION NWAVE and QC XXX RESOLUTION MEANRMS
#
# Revision 1.8.6.6 2006/07/18 06:45:34 cizzo
# Add QC LAMP FLUX and QC LAMP FLUXERR, and extend to MXU the spectral resolution QC
#
# Revision 1.8.6.5 2005/09/01 11:27:12 cizzo
# Correct a typo
#
# Revision 1.8.6.4 2005/09/01 11:23:06 cizzo
# Add new QC1 parameters
#
# Revision 1.8.6.3 2005/07/15 06:34:19 cizzo
# Add parameter QC ZPOINT NSTARS
#
# Revision 1.8.6.2 2005/07/07 12:46:33 cizzo
# Add OUTi FLAT EFF
#
# Revision 1.8.6.1 2005/07/06 13:24:03 cizzo
# New QC1 parameters added
#
# Revision 1.8 2001/06/21 14:45:26 sbogun
# dicFORS-QC1.8
#
# Revision 1.7 2001/06/21 12:49:06 vltsccm
# dicFORS-QC1.7
#
# Revision 1.6 2001/06/21 12:33:22 vltsccm
# dicFORS-QC1.6
#
#******************************************************************************
# NAME
# ESO-DFS-DIC.FORS_QC - Data Interface Dictionary for FORS Quality control
# parameters.
# -----------------------------------------------------------------------------
Dictionary Name: ESO-DFS-DIC.FORS_QC
Scope: QC
Source: ESO DFS/DMD
Version Control: "@(#) $Id: ESO-DFS-DIC.FORS2_QC,v 1.17 2011-10-05 16:03:34 cgarcia Exp $"
Revision: 1.5
Date: 2001-02-20
Status: draft
Description: Keywords related to bias and flat field frames added.
Revision: 1.6
Date: 2001-03-07
Status: draft
Description: Date field made ISO 8601 conform
Revision: 1.7
Date: 2001-04-25
Status: submitted
Description: Changes due to QC dictionary alignment with other instr.
Revision: 1.8
Date: 2001-05-29
Status: submitted
Description: Comments from DICB incorporated
Revision: 2.0
Date: 2005-09-01
Status: submitted
Description: New QC1 parameters added
Revision: 3.0
Date: 2007-10-04
Status: submitted
Description: Imaging QC1 parameters entirely revised
# QC Category
Parameter Name: QC DID
Class: header|qc-log
Context: process
Type: string
Value Format: %30s
Unit:
Comment Field: Data dictionary for QC
Description: Name/version of ESO DID to which QC keywords comply.
Parameter Name: QC OVEREXPO
Class: header|qc-log
Context: process
Type: double
Value Format: %e
Unit:
Comment Field: Percentage of overexposed pixels (%)
Description: This quantity is computed by recipes fors_img_screen_flat
and fors_img_sky_flat. It is derived from the input raw
flat fields frames (sky and screen), and associated to
the produced master calibrations. A saturated pixel is
defined as a pixel having value either 65535 or 0 ADUs.
In its practical implementation, a saturated pixel is
identified by having a value either greater than 65534
or less than 1 ADUs. Saturated pixels are counted in the
original raw frames before any processing (including bias
subtraction), and excluding the overscan regions. The
total number of saturated pixels is divided by the total
number of pixels examined in all input raw frames, and
the result is multiplied by 100.
Parameter Name: QC SKYAVG
Class: header|qc-log
Context: process
Type: double
Value Format: %e
Unit: mag/arcsec^2
Comment Field: Mean of sky background (mag/arcsec^2)
Description: This quantity is determined by the recipe fors_img_science.
The background determination is part of the source
extraction algorithm (provided by SExtractor). This
QC parameter is defined as M = -2.5*log10(F/A), where F
is the mean of the background map, and A the area of
one image pixel in arcsec^2. Note that this is an
instrumental magnitude, where no color correction
is applied.
Parameter Name: QC SKYMED
Class: header|qc-log
Context: process
Type: double
Value Format: %e
Unit: mag/arcsec^2
Comment Field: Median of sky background (mag/arcsec^2)
Description: This quantity is determined by the recipe fors_img_science.
The background determination is part of the source
extraction algorithm (provided by SExtractor). This
QC parameter is defined as M = -2.5*log10(F/A), where F
is the median of the background map, and A the area
of one image pixel in arcsec^2. Note that this is an
instrumental magnitude, where no color correction is
applied.
Parameter Name: QC SKYRMS
Class: header|qc-log
Context: process
Type: double
Value Format: %e
Unit: mag/arcsec^2
Comment Field: Standard deviation of sky background (mag/arcsec^2)
Description: This quantity is determined by the recipe fors_img_science,
and is defined as the standard deviation of the smoothed
background level from its median value. The standard
deviation is determined in term of flux (ADU/s) and then
propagated to instrumental magnitude units. More
specifically, if dF is the variation of flux, the
corresponding variation in magnitudes dM is the differential
of M = -2.5*log10(F/A), dM = -2.5*log10(e)*dF/F. The
background determination is part of the source extraction
algorithm (provided by SExtractor).
Parameter Name: QC IMGQU
Class: header|qc-log
Context: process
Type: double
Value Format: %e
Unit: arcsec
Comment Field: Image quality of scientific exposure (arcsec)
Description: This quantity is determined by the recipe fors_img_science.
Image quality is defined as the median FWHM (as computed by
SExtractor) of stars detected on a calibrated scientific
exposure. An object is considered a star if the
corresponding SExtractor stellarity index is greater than
0.7 and the FWHM is larger than 1 pixel.
Parameter Name: QC IMGQUERR
Class: header|qc-log
Context: process
Type: double
Value Format: %e
Unit: arcsec
Comment Field: Uncertainty of image quality (arcsec)
Description: This quantity is determined by the recipe fors_img_science.
Uncertainty of the FWHM values used in the computation
of QC IMGQU. This is computed as the population standard
deviation of the FWHM values obtained for each detected
source from their median value (see parameter QC IMGQU).
Parameter Name: QC STELLAVG
Class: header|qc-log
Context: process
Type: double
Value Format: %e
Unit:
Comment Field: Mean stellarity index
Description: This quantity is determined by the recipe fors_img_science.
Mean SExtractor stellarity index of all objects used for
QC IMGQU computation.
Parameter Name: QC IMGQUELL
Class: header|qc-log
Context: process
Type: double
Value Format: %e
Unit:
Comment Field: Mean star ellipticity
Description: This quantity is determined by the recipe fors_img_science.
Mean ellipticity of all objects used for QC IMGQU
computation.
Parameter Name: QC IMGQUELLERR
Class: header|qc-log
Context: process
Type: double
Value Format: %e
Unit:
Comment Field: Standard deviation of star ellipticities
Description: This quantity is determined by the recipe fors_img_science.
It is computed as 0.6745 times the median absolute deviation
with respect to the median of all objects used for QC IMGQU
computation with respect to the median ellipticity.
Parameter Name: QC ZPOINT
Class: header|qc-log
Context: process
Type: double
Value Format: %e
Unit: mag
Comment Field: Frame zeropoint (mag)
Description: Frame zeropoint, computed by recipe fors_zeropoint from
one photometric standard star field exposure as the
optimally weighted mean (1/variance weights) of the
difference between the catalog magnitude and the
corrected instrumental magnitude, with rejection of
outliers (see ahead about the applied rejection criteria).
The corrected instrumental magnitude is derived from the
observed instrumental magnitude converting the source
counts into electrons per second, and porting the result
to airmass 0 keeping into account the color index of the
star. That means:
corr. mag. = obs. mag.
+ 2.5 * log_10(exptime)
+ 2.5 * log_10(gain[ADU/e-])
- |extcoeff(filter)|*airmass
+ color_term(filter)*color_index(filter, star)
The zeropoints for each star are used in the mean
zeropoint computation only if they differ less than
max(k*sigma, E) from their median value, where sigma
is the computed statistical error for a single zeropoint,
k the number of sigmas required for rejection, and E
an expected systematic error (k and E can be user-defined,
and they are defaulted respectively to 5 and 0.3).
Parameter Name: QC ZPOINTRMS
Class: header|qc-log
Context: process
Type: double
Value Format: %e
Unit: mag
Comment Field: Uncertainty of frame zeropoint (mag)
Description: This quantity is computed by recipe fors_zeropoint.
The reported zeropoint error is the random statistical
error only (propagated both from observed and catalog
quantities).
Parameter Name: QC ZPOINT NSTARS
Class: header|qc-log
Context: process
Type: int
Value Format: %d
Unit:
Comment Field: Number of stars used for zeropoint computation
Description: Number of stars used for zeropoint computation by recipe
fors_zeropoint.
Parameter Name: QC ZPOINT NSRCEXTRACT
Class: header|qc-log
Context: process
Type: int
Value Format: %d
Unit:
Comment Field: Number of stars detected in the zeropoint image
Description: Number of stars detected by sextractor in the zeropoint image
by recipe fors_zeropoint.
Parameter Name: QC EXTCOEFF
Class: header|qc-log
Context: process
Type: double
Value Format: %e
Unit: mag/airmass
Comment Field: Atmospheric extinction (mag/airmass)
Description: This quantity is computed by the recipe fors_zeropoint.
It is the atmospheric extinction coefficient E required
to explain the difference between Z = QC ZPOINT and the
nominal expected zeropoint Zo given as input to the recipe,
that is E = (Zo - Z)/A + Eo, where A is the airmass, and
Eo is the atmospheric extinction coefficient that was assumed
for the computation of Z.
Parameter Name: QC EXTCOEFFERR
Class: header|qc-log
Context: process
Type: double
Value Format: %e
Unit: mag/airmass
Comment Field: Error on atmospheric extinction (mag/airmass)
Description: This is the result of error propagation on the
computation of the atmospheric extinction
(QC EXTCOEFF).
Parameter Name: QC INSTRUMENT ZEROPOINT
Class: header|qc-log
Context: process
Type: double
Value Format: %e
Unit: mag
Comment Field: Instrument zeropoint (mag)
Description: This quantity is computed by the recipe fors_photometry
if -fitz=false.
Parameter Name: QC INSTRUMENT ZEROPOINT ERROR
Class: header|qc-log
Context: process
Type: double
Value Format: %e
Unit: mag
Comment Field: Error on instrument zeropoint (mag)
Description: Error on QC INSTRUMENT ZEROPOINT (1 sigma).
Parameter Name: QC ATMOSPHERIC EXTINCTION
Class: header|qc-log
Context: process
Type: double
Value Format: %e
Unit: mag/airmass
Comment Field: Atmospheric extinction (mag/airmass)
Description: This quantity is computed by the recipe fors_photometry
if -fitx=true.
Parameter Name: QC ATMOSPHERIC EXTINCTION ERROR
Class: header|qc-log
Context: process
Type: double
Value Format: %e
Unit: mag/airmass
Comment Field: Error on atmospheric extinction (mag/airmass)
Description: Error on QC ATMOSPHERIC EXTINCTION (1 sigma).
Parameter Name: QC COLOR CORRECTION
Class: header|qc-log
Context: process
Type: double
Value Format: %e
Unit:
Comment Field: Linear color correction term
Description: This quantity is computed by the recipe fors_photometry
if -fitc=true.
Parameter Name: QC COLOR CORRECTION ERROR
Class: header|qc-log
Context: process
Type: double
Value Format: %e
Unit:
Comment Field: Error on linear color correction term
Description: Error on QC COLOR CORRECTION (1 sigma).
Parameter Name: QC BIAS LEVEL
Class: header|qc-log
Context: process
Type: double
Value Format: %e
Unit: ADU
Comment Field: Bias level (ADU)
Description: This quantity is computed by recipe fors_bias. The
bias level is evaluated as the median value of all pixels
of the first raw bias in the input set-of-frames after
overscan subtraction.
Parameter Name: QC RON
Class: header|qc-log
Context: process
Type: double
Value Format: %e
Unit: ADU
Comment Field: Readout noise (ADU)
Description: This quantity is computed by the recipe fors_bias.
The difference between the first and the second input
raw biases is computed. The standard deviation of the
pixel values of this difference, divided by the square
root of 2, is taken as the RON.
Parameter Name: QC BIAS FPN
Class: header|qc-log
Context: process
Type: double
Value Format: %e
Unit: ADU
Comment Field: Bias fixed pattern (ADU)
Description: This quantity is computed by recipe fors_bias. The
difference between the first two input raw bias frames,
the second one shifted by 10x10 pixels in the increasing
X- and Y-directions, is computed (where possible). The
variance of the difference frame includes contributions of
both fixed pattern and read out noise. The standard
deviation of the difference is computed and divided by
sqrt(2). The readout noise contribution QC RON is then
quadratically subtracted from the result.
Parameter Name: QC BIAS STRUCT
Class: header|qc-log
Context: process
Type: double
Value Format: %e
Unit: ADU
Comment Field: Bias structure (ADU)
Description: This quantity is computed by recipe fors_bias. The
standard deviation of the pixel values of the first
input raw bias is computed. This is the combination
of structure, fixed pattern, and readout noise.
The readout noise QC RON and the fixed pattern
QC BIAS FPN contributions are then quadratically
subtracted.
Parameter Name: QC MBIAS LEVEL
Class: header|qc-log
Context: process
Type: double
Value Format: %e
Unit: ADU
Comment Field: Master bias level (ADU)
Description: This quantity is computed by recipe fors_bias. The
master bias level is evaluated as the median value of all pixels
of the master bias after overscan subtraction.
Parameter Name: QC MBIAS RONEXP
Class: header|qc-log
Context: process
Type: double
Value Format: %.3f
Unit: ADU
Comment Field: Expected master bias readout noise (ADU)
Description: This quantity is computed by the recipe fors_bias.
The expected master bias readout noise is computed propagating
the measured RON (QC RON) according to the number of raw bias
frames and stacking method.
Parameter Name: QC MBIAS NOISE
Class: header|qc-log
Context: process
Type: double
Value Format: %e
Unit: ADU
Comment Field: Master bias noise (ADU)
Description: This quantity is computed by the recipe fors_bias.
The median master bias is determined. The standard
deviation of the pixel values from this median level is
determined, excluding from the computation all values
that differ from it more than 3 * QC MBIAS RONEXP.
This is done in the attempt to minimise deviations
not caused by RON.
Parameter Name: QC MBIAS NRATIO
Class: header|qc-log
Context: process
Type: double
Value Format: %.3f
Unit:
Comment Field: Master bias observed/expected noise
Description: This quantity is computed by the recipe fors_bias.
The ratio between QC MBIAS NOISE and QC MBIAS RONEXP
by the square root of the number of raw bias frames used
in the construction of the master bias, is computed.
This ratio is expected to be 1, but it may be less
than 1 because of RON overestimation due to incoherent
pickup noise, or more than 1 in case of coherent pickup
noise that would remain unchanged on the result master
bias.
Parameter Name: QC MBIAS STRUCT
Class: header|qc-log
Context: process
Type: double
Value Format: %.3f
Unit: ADU
Comment Field: Structure of master bias (ADU)
Description: This quantity is computed by the recipe fors_bias.
The structure is computed as the standard deviation
of all master bias pixels values minus the value of
QC MBIAS NOISE (geometrically subtracted).
Parameter Name: QC FLAT EFF
Class: header|qc-log
Context: process
Type: double
Value Format: %.3f
Unit: ADU/s
Comment Field: Flat field lamp efficiency (ADU/s)
Description: This quantity is computed by recipe fors_img_screen_flat.
The efficiency is computed as the median of all pixels
of the first input raw frame (bias subtracted, and dark
subtracted if a dark is provided), divided by its exposure
time.
Parameter Name: QC FLAT PHN
Class: header|qc-log
Context: process
Type: double
Value Format: %.3f
Unit: ADU
Comment Field: Photon noise in master screen flat field (ADU)
Description: This quantity is computed by recipe fors_img_screen_flat.
The photon noise is estimated in the following way:
the difference frame between the first two input raw
flat field frames is determined for their central 100x100
region. The standard deviation of all pixels of this
difference frame is computed, and then divided by sqrt(2N)
where N is the total number of raw flat field frames
contributing to the master flat field. The RON is
considered negligible in the computation of PHN.
Parameter Name: QC FLAT FPN
Class: header|qc-log
Context: process
Type: double
Value Format: %.3f
Unit: ADU
Comment Field: Fixed-pattern noise (ADU)
Description: This quantity is computed by recipe fors_img_screen_flat.
The FPN is computed in the following way: The difference
of two 100x100 sub-frames of the same master flat field
image is determined. The first subframe is extracted at
the frame center, while the second is extracted from a
position shifted by 10 pixels in the increasing X- and
Y-directions. The standard deviation of the difference
frame, divided by sqrt(2), minus the photon noise
QC FLAT PHN (geometrically subtracted) yields the
fixed-pattern noise. The RON is considered negligible
in the computation of PHN.
Parameter Name: QC FLAT FPN REL
Class: header|qc-log
Context: process
Type: double
Value Format: %.3f
Unit:
Comment Field: Relative fixed-pattern noise
Description: This quantity is the fixed pattern noise (QC FLAT FPN)
divided by the median illumination level of the flat
field exposure.
Parameter Name: QC FLAT CONAD
Class: header|qc-log
Context: process
Type: double
Value Format: %e
Unit: e-/ADU
Comment Field: Conversion factor from ADU to electrons (e-/ADU)
Description: This quantity is computed by recipe fors_img_screen_flat.
If the exposure time of the first two input raw screen
flat fields in the input set of frames is the same
(within 4%), the absolute difference frame is computed. At
each pixel the difference frame is divided by 2 and by the
signal of the first frame. This frame estimates the gain (in
ADU/e-) at each pixel, and the conversion factor is computed
as the reciprocal mean of this frame.
Parameter Name: QC FLAT CONADERR
Class: header|qc-log
Context: process
Type: double
Value Format: %e
Unit: e-/ADU
Comment Field: Error on conversion factor ADU/electrons (e-/ADU)
Description: This quantity is computed by recipe fors_img_screen_flat.
It is computed as the standard deviation of the gain frame,
also used for the computation of QC FLAT CONAD, multiplied
by QC FLAT CONAD squared.
Parameter Name: QC SKYFLAT FLUX MIN
Class: header|qc-log
Context: process
Type: double
Value Format: %e
Unit: ADU
Comment Field: Median level of dimmest input raw sky flat (ADU)
Description: This quantity is computed by recipe fors_img_sky_flat_impl.
Parameter Name: QC SKYFLAT FLUX MAX
Class: header|qc-log
Context: process
Type: double
Value Format: %e
Unit: ADU
Comment Field: Median level of brightest input raw sky flat (ADU)
Description: This quantity is computed by recipe fors_img_sky_flat_impl.
Parameter Name: QC LSS CENTRAL WAVELENGTH
Class: header|qc-log
Context: process
Type: double
Value Format: %.3f
Unit: Angstrom
Comment Field: Wavelength at CCD center (Angstrom)
Description: After the wavelength calibration is obtained from an LSS
arc lamp exposure, the wavelength corresponding to the
central CCD pixel is calculated.
Parameter Name: QC MOS CENTRAL WAVELENGTH
Class: header|qc-log
Context: process
Type: double
Value Format: %.3f
Unit: Angstrom
Comment Field: Wavelength at the center of slit 10 (Angstrom)
Description: After the wavelength calibration is obtained from a MOS
arc lamp exposure, the wavelength corresponding to the
center of slit 10 is computed.
Parameter Name: QC PMOS CENTRAL WAVELENGTH
Class: header|qc-log
Context: process
Type: double
Value Format: %.3f
Unit: Angstrom
Comment Field: Wavelength at CCD center (Angstrom)
Description: After the wavelength calibration is obtained from a PMOS
arc lamp exposure with all slitlets at equal offset 0,
the wavelength corresponding to the central CCD pixel
is calculated.
Parameter Name: QC WAVE ACCURACY
Class: header|qc-log
Context: process
Type: double
Value Format: %.3f
Unit: Pixel
Comment Field: Mean accuracy of wavelength calibration (Pixel)
Description: This quantity is computed by recipe fors_calib.
This is the mean accuracy of the wavelength calibration
fits on all spectra. It is derived from the standard
deviation of the residuals of the fits, corrected
for the number of fitted point and degrees of freedom
of the fitting polynomial: sigma/sqrt(npoint/nfree).
Parameter Name: QC WAVE ACCURACY ERROR
Class: header|qc-log
Context: process
Type: double
Value Format: %.3f
Unit: Pixel
Comment Field: Error on mean accuracy of wavelength calibration (Pixel)
Description: This quantity is computed by recipe fors_calib.
This is the mean accuracy of the wavelength calibration
fits on all spectra. It is derived from the standard
deviation of the mean accuracies of all fits.
Parameter Name: QC LSS RESOLUTION
Class: header|qc-log
Context: process
Type: double
Value Format: %e
Unit:
Comment Field: Mean spectral resolution of all identified arc lamp lines.
Description: From a wavelength calibrated LSS arc lamp exposure, the
mean spectral resolution from all lines in catalog is
computed. Each single spectral resolution is computed
as the ratio between the arc lamp line wavelength and
its FWHM.
Parameter Name: QC LSS RESOLUTION RMS
Class: header|qc-log
Context: process
Type: double
Value Format: %e
Unit:
Comment Field: Population RMS of all computed spectral resolutions.
Description: Population RMS of all values contributing to the mean
spectral resolution (QC LSS RESOLUTION).
Parameter Name: QC LSS RESOLUTION NLINES
Class: header|qc-log
Context: process
Type: int
Value Format: %d
Unit:
Comment Field: Number of lines used for computing QC LSS RESOLUTION.
Description: Number of lines used in the computation of parameter
QC LSS RESOLUTION.
Parameter Name: QC LSS RESOLUTION NWAVE
Class: header|qc-log
Context: process
Type: int
Value Format: %d
Unit:
Comment Field: Number of wavelengths used for computing QC LSS RESOLUTION.
Description: Number of wavelengths used in the computation of parameter
QC LSS RESOLUTION.
Parameter Name: QC LSS RESOLUTION MEANRMS
Class: header|qc-log
Context: process
Type: double
Value Format: %e
Unit:
Comment Field: Mean RMS of spectral resolutions at each wavelength.
Description: Mean RMS of in the determination of the spectral
resolution at each wavelength.
Parameter Name: QC MOS RESOLUTION
Class: header|qc-log
Context: process
Type: double
Value Format: %e
Unit:
Comment Field: Mean spectral resolution of all identified arc lamp lines.
Description: From a wavelength calibrated MOS arc lamp exposure, the
mean spectral resolution from all lines in catalog is
computed. Each single spectral resolution is computed
as the ratio between the arc lamp line wavelength and
its FWHM.
Parameter Name: QC MOS RESOLUTION RMS
Class: header|qc-log
Context: process
Type: double
Value Format: %e
Unit:
Comment Field: Population RMS of all computed spectral resolutions.
Description: Population RMS of all values contributing to the mean
spectral resolution (QC MOS RESOLUTION).
Parameter Name: QC MOS RESOLUTION NLINES
Class: header|qc-log
Context: process
Type: int
Value Format: %d
Unit:
Comment Field: Number of lines used for computing QC MOS RESOLUTION.
Description: Number of lines used in the computation of parameter
QC MOS RESOLUTION.
Parameter Name: QC MOS RESOLUTION NWAVE
Class: header|qc-log
Context: process
Type: int
Value Format: %d
Unit:
Comment Field: Number of wavelengths used for computing QC MOS RESOLUTION.
Description: Number of wavelengths used in the computation of parameter
QC MOS RESOLUTION.
Parameter Name: QC MOS RESOLUTION MEANRMS
Class: header|qc-log
Context: process
Type: double
Value Format: %e
Unit:
Comment Field: Mean RMS of spectral resolutions at each wavelength.
Description: Mean RMS of in the determination of the spectral
resolution at each wavelength.
Parameter Name: QC MXU RESOLUTION
Class: header|qc-log
Context: process
Type: double
Value Format: %e
Unit:
Comment Field: Mean spectral resolution of all identified arc lamp lines.
Description: From a wavelength calibrated MXU arc lamp exposure, the
mean spectral resolution from all lines in catalog is
computed. Each single spectral resolution is computed
as the ratio between the arc lamp line wavelength and
its FWHM.
Parameter Name: QC MXU RESOLUTION RMS
Class: header|qc-log
Context: process
Type: double
Value Format: %e
Unit:
Comment Field: Population RMS of all computed spectral resolutions.
Description: Population RMS of all values contributing to the mean
spectral resolution (QC MXU RESOLUTION).
Parameter Name: QC MXU RESOLUTION NLINES
Class: header|qc-log
Context: process
Type: int
Value Format: %d
Unit:
Comment Field: Number of lines used for computing QC MXU RESOLUTION.
Description: Number of lines used in the computation of parameter
QC MXU RESOLUTION.
Parameter Name: QC MXU RESOLUTION NWAVE
Class: header|qc-log
Context: process
Type: int
Value Format: %d
Unit:
Comment Field: Number of wavelengths used for computing QC MXU RESOLUTION.
Description: Number of wavelengths used in the computation of parameter
QC MXU RESOLUTION.
Parameter Name: QC MXU RESOLUTION MEANRMS
Class: header|qc-log
Context: process
Type: double
Value Format: %e
Unit:
Comment Field: Mean RMS of spectral resolutions at each wavelength.
Description: Mean RMS of in the determination of the spectral
resolution at each wavelength.
Parameter Name: QC LAMP FLUX
Class: header|qc-log
Context: process
Type: double
Value Format: %e
Unit: ADU/pixel/s
Comment Field: Calibration lamp flux (ADU/pixel/s)
Description: This parameter is determined on a bias subtracted
calibration lamp exposure in LSS mode, generally
obtained with the 300V grism. After the background
subtraction the total signal is integrated and divided
by the exposure time and by the total number of CCD
original pixels (keeping into account a possible
rebinned readout). In the case of FORS2 frames the
background is the median level evaluated from the
available overscan regions. In the case of FORS1 data,
where overscan regions are missing, the background is
evaluated as the median level of the first 200 CCD
columns for flat field data, while for arc lamp data
a background map evaluated from the regions without
spectral lines is computed and subtracted.
Parameter Name: QC LAMP FLUXERR
Class: header|qc-log
Context: process
Type: double
Value Format: %e
Unit: ADU/pixel/s
Comment Field: Error on calibration lamp flux (ADU/pixel/s)
Description: The statistical error on the parameter QC LAMP FLUX
is computed as sqrt(S/gain), where S is the total counts
(in ADU) from the explored region, and gain is the
conversion factor from ADU to electrons. This value is
then converted to the same units of QC LAMP FLUX.
Parameter Name: QC TRACE MAX CURVATURE
Class: header|qc-log
Context: process
Type: double
Value Format: %e
Unit: Y pixel/ X pixel ^2
Comment Field: Max curvature in spectral tracing (Y pixel/X pixel^2)
Description: This is computed by recipe fors_calib as the max
absolute value of the column "c2" of the CURV_COEFF
table.
Parameter Name: QC TRACE MAX SLOPE
Class: header|qc-log
Context: process
Type: double
Value Format: %e
Unit: Y pixel/ X pixel
Comment Field: Max curvature in spectral tracing (Y pixel/X pixel)
Description: This is computed by recipe fors_calib as the max
absolute value of the column "c1" of the CURV_COEFF
table.
Parameter Name: QC SPEC EFFICIENCYi
Class: header|qc-log
Context: process
Type: double
Value Format: %e
Unit: e-/photon
Comment Field: Value of efficiency at given wavelength (e-/photon)
Description: The efficiency curve is computed as the ratio between
the standard star catalog fluxes converted to photons
(per second per Angstrom), and the observed standard
star spectrum converted to electrons (per second per
Angstrom). This curve is then smoothed by a heavy
median filter and then fitted by a high degree
polynomial, to obtain a smooth efficiency curve
unaffected by local atmospheric absorbtions and
by uncertainties around the absorbtion lines in the
standard star spectral continuum. The values of the
efficiency at different wavelengths are read from
this smoothed curve.
Parameter Name: QC SPEC EFFICIENCYi LAMBDA
Class: header|qc-log
Context: process
Type: double
Value Format: %e
Unit: Angstrom
Comment Field: Wavelength at which the efficiency was measured (Angstrom)
Description: Wavelength at which the efficiency was measured.
Parameter Name: QC PMOS BAND
Class: header|qc-log
Context: process
Type: string
Value Format: %s
Unit:
Comment Field: Band where polarisation was measured (U, B, V, R, I)
Description: Band where the linear polarisation of a standard
star was measured (U, B, V, R, I)
Parameter Name: QC PMOS POLARISED
Class: header|qc-log
Context: process
Type: integer
Value Format: %d
Unit:
Comment Field: Polarisation is expected (1 = yes, 0 = no)
Description: The standard star is not expected to be linearly
polarised if this parameter is set to 0.
Parameter Name: QC PMOS L OFFSET
Class: header|qc-log
Context: process
Type: double
Value Format: %e
Unit:
Comment Field: Deviation from expected linear polarisation.
Description: If QC.PMOS.POLARISED = 1, linear polarisation
relative offset (observed minus expected divided
by expected); if QC.PMOS.POLARISED = 0, linear
polarisation absolute offset (observed minus
expected).
Parameter Name: QC PMOS L OFFSETERR
Class: header|qc-log
Context: process
Type: double
Value Format: %e
Unit:
Comment Field: Error on QC.PMOS.L.OFFSET
Description: Error on QC.PMOS.L.OFFSET
Parameter Name: QC PMOS ANGLE OFFSET
Class: header|qc-log
Context: process
Type: double
Value Format: %e
Unit: degrees
Comment Field: Polarisation angle offset (degrees)
Description: Polarisation angle offset (observed minus expected),
only written if QC.PMOS.POLARISED = 1
Parameter Name: QC PMOS ANGLE OFFSETERR
Class: header|qc-log
Context: process
Type: double
Value Format: %e
Unit: degrees
Comment Field: Error on QC.PMOS.ANGLE.OFFSET (degrees)
Description: Error on QC.PMOS.ANGLE.OFFSET, only written if
QC.PMOS.POLARISED = 1
Parameter Name: QC NANGLES OFFSETERR
Class: header|qc-log
Context: process
Type: int
Value Format: %e
Unit:
Comment Field: Number of exposures used for computing Stokes parameter.
Description: This parameter is written to the header of images
containing the Q, U, V extracted Stokes parameters.
|
