DECam Instrumental Signature Removal

I think so. Do you have the cross talk coefficients for every (CCD, Amp) pair? That’d tell us how important this is

All of the CP calibration products can be grabbed from ftp.
http://www.ctio.noao.edu/noao/content/DECam-Calibration-Files
Here’s the command:
ftp ftp://ftp.noao.edu/pub/valdes/DECamCPCalFiles150123/
I would attach the xtalk file, but discourse doesn’t support attaching files yet.

Not sure if this is a good idea, but I’m pasting in the full xtalk file:

# victim source  x   x_err    src_nl      poly_coeff
ccd25B   ccd25A      1.34e-04   1.13e-05    4.078154e+04  1.537540e-04  -6.980507e-08  5.963848e-12  
ccd25A   ccd25B      3.16e-04   9.32e-06    4.038128e+04  8.826313e-04  -1.619436e-07  9.457412e-12  
ccd26A   ccd25A      2.95e-05   5.49e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd26A   ccd25B      3.90e-05   3.28e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd26B   ccd25B      4.10e-05   3.65e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd26B   ccd26A      -5.36e-04   6.86e-06    4.373232e+04  -6.703301e-04  3.463778e-08  9.838246e-13  
ccd26A   ccd26B      4.50e-04   7.61e-06    4.076989e+04  8.639303e-04  -1.609836e-07  1.079198e-11  
ccd27A   ccd26A      2.38e-05   3.12e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd27B   ccd26B      2.27e-05   3.88e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd25B   ccd27B      -1.73e-05   5.30e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd26B   ccd27A      -2.31e-05   3.77e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd26A   ccd27B      -2.30e-05   6.04e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd27B   ccd27A      -7.18e-04   6.54e-06    4.493235e+04  -4.119533e-04  2.331235e-08  8.012798e-13  
ccd27A   ccd27B      4.47e-04   7.53e-06    4.477443e+04  5.793412e-04  -3.940148e-08  1.767087e-12  
ccd32B   ccd32A      -8.28e-04   7.16e-06    4.235143e+04  -1.642225e-03  2.683240e-07  -1.266185e-11  
ccd32A   ccd32B      3.40e-04   6.32e-06    4.350554e+04  2.837990e-04  -1.316717e-08  2.130434e-12  
ccd33B   ccd33A      1.14e-04   5.61e-06    4.328240e+04  7.174996e-05  4.829730e-08  -3.226365e-12  
ccd33A   ccd33B      3.28e-04   6.41e-06    4.548654e+04  7.434658e-04  -1.614734e-07  1.313377e-11  
ccd34A   ccd33A      3.61e-05   2.65e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd34B   ccd33B      3.05e-05   1.79e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd34B   ccd34A      -5.23e-04   6.34e-06    4.472627e+04  -6.161739e-04  1.275022e-07  -6.630950e-12  
ccd34A   ccd34B      1.39e-04   8.52e-06    4.314007e+04  4.483086e-05  -3.110871e-08  4.991906e-12  
ccd04B   ccd04A      -4.76e-04   7.30e-06    4.000246e+04  -7.698136e-04  4.817214e-08  -5.138844e-13  
ccd04A   ccd04B      1.48e-04   1.18e-05    4.061272e+04  -1.640558e-04  5.410541e-08  -2.150999e-12  
ccd04A   ccd08A      3.86e-05   3.40e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd04B   ccd08B      2.10e-05   3.22e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd08B   ccd08A      1.10e-04   5.48e-06    4.061000e+04  2.363033e-04  -5.439024e-08  3.462319e-12  
ccd08A   ccd08B      2.50e-04   7.03e-06    4.545600e+04  1.506182e-04  -2.772457e-08  3.520614e-12  
ccd13B   ccd13A      -7.52e-04   7.41e-06    4.091800e+04  -9.248876e-04  4.529715e-08  -7.223878e-14  
ccd13A   ccd13B      3.68e-04   5.28e-06    4.215807e+04  1.284040e-04  1.685578e-09  2.180761e-12  
ccd14A   ccd13A      3.27e-05   4.21e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd14B   ccd13B      3.82e-05   4.35e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd04A   ccd14A      3.58e-05   3.56e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd14B   ccd14A      -6.69e-04   5.79e-06    4.261907e+04  -1.085696e-03  1.151814e-07  -3.468178e-12  
ccd14A   ccd14B      5.42e-04   8.90e-06    4.119961e+04  4.155819e-04  -2.755728e-08  3.903702e-12  
ccd19B   ccd19A      1.56e-04   6.10e-06    4.273072e+04  -3.673395e-04  5.520903e-08  -7.037529e-13  
ccd19A   ccd19B      3.07e-04   7.31e-06    4.557400e+04  -4.371844e-04  1.394320e-07  -4.005219e-12  
ccd20A   ccd19A      3.63e-05   3.63e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd20A   ccd19B      3.60e-05   4.79e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd20B   ccd19B      3.98e-05   3.08e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd13A   ccd20A      1.65e-05   4.01e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd13B   ccd20B      2.68e-05   3.37e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd20B   ccd20A      -5.55e-04   7.07e-06    4.073200e+04  -1.154366e-03  1.365805e-07  -4.639454e-12  
ccd20A   ccd20B      4.41e-04   9.19e-06    4.062650e+04  3.416947e-04  -2.926711e-08  3.219866e-12  
ccd39B   ccd39A      3.41e-04   5.47e-06    4.324480e+04  -7.953314e-05  8.510185e-08  -3.924838e-12  
ccd39A   ccd39B      6.58e-04   1.10e-05    4.677212e+04  9.891268e-04  -1.287373e-07  1.259077e-11  
ccd40A   ccd39A      2.98e-05   4.01e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd40A   ccd39B      2.03e-05   3.15e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd40B   ccd39B      3.67e-05   3.16e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd40B   ccd40A      -5.70e-04   8.58e-06    4.140226e+04  -7.382333e-04  8.558701e-08  -3.091537e-12  
ccd40A   ccd40B      4.63e-04   6.32e-06    4.187307e+04  3.896951e-04  3.524695e-08  -2.698712e-12  
ccd45A   ccd40A      2.53e-05   2.35e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd45B   ccd40B      3.46e-05   2.98e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd45B   ccd45A      -7.12e-04   4.77e-06    4.002995e+04  -1.052282e-03  5.778108e-08  -7.473609e-13  
ccd45A   ccd45B      4.84e-04   9.84e-06    4.927645e+04  6.848641e-04  -4.371973e-08  -1.367840e-12  
ccd46B   ccd45B      3.80e-05   2.48e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd39A   ccd46A      -2.90e-05   5.83e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd46B   ccd46A      -6.84e-04   4.10e-06    4.604700e+04  1.794597e-04  -6.552887e-07  1.445779e-10  
ccd46A   ccd46B      4.54e-04   9.50e-06    4.202477e+04  3.081697e-04  -1.486023e-07  2.413996e-11  
ccd51B   ccd51A      1.12e-04   4.97e-06    4.229637e+04  -7.621760e-05  5.317283e-08  -2.667998e-12  
ccd51A   ccd51B      3.40e-04   6.99e-06    4.575949e+04  5.373012e-04  -5.345298e-08  5.393547e-12  
ccd56A   ccd51A      3.45e-05   3.69e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd56B   ccd51B      3.42e-05   3.28e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd56B   ccd56A      -4.88e-04   5.96e-06    4.053117e+04  -5.247658e-04  1.262565e-08  1.284578e-12  
ccd56A   ccd56B      1.73e-04   7.95e-06    4.484066e+04  3.399175e-04  -7.278292e-08  6.769633e-12  
ccd17B   ccd17A      1.91e-04   5.81e-06    4.346934e+04  -5.713013e-04  9.681892e-08  -3.194457e-12  
ccd17A   ccd17B      4.08e-04   9.73e-06    4.369112e+04  4.101070e-04  -1.938186e-09  2.884910e-12  
ccd18A   ccd17A      3.76e-05   2.56e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd18A   ccd17B      9.66e-05   3.86e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd18B   ccd18A      -6.46e-04   4.85e-06    4.240534e+04  -1.103450e-03  1.659122e-07  -7.609292e-12  
ccd18A   ccd18B      1.27e-04   9.66e-06    4.516890e+04  3.508282e-04  -2.761238e-08  -2.123464e-12  
ccd21B   ccd21A      2.78e-04   8.01e-06    4.086850e+04  -3.603690e-04  5.800177e-08  -6.254689e-13  
ccd21A   ccd21B      3.86e-04   6.76e-06    4.356114e+04  1.019117e-05  4.712910e-08  3.005622e-13  
ccd22A   ccd21A      4.89e-05   1.75e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd22A   ccd21B      1.15e-04   3.11e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd22B   ccd21B      5.56e-05   2.22e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd22B   ccd22A      -4.92e-04   6.69e-06    4.645904e+04  -2.126832e-04  1.419536e-07  -1.051436e-11  
ccd22A   ccd22B      3.64e-04   7.00e-06    4.078500e+04  3.129247e-04  -2.944141e-08  3.184816e-12  
ccd23A   ccd22A      4.48e-05   4.16e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd23A   ccd22B      7.04e-05   5.23e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd23B   ccd22B      3.91e-05   3.39e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd23B   ccd23A      -9.18e-04   6.02e-06    4.219063e+04  -1.545775e-03  2.520741e-07  -1.278086e-11  
ccd23A   ccd23B      3.29e-04   9.37e-06    4.295030e+04  6.296770e-04  -8.378071e-08  7.049358e-12  
ccd24A   ccd23A      2.73e-05   3.77e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd24B   ccd23B      7.05e-05   3.33e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd17A   ccd24A      7.42e-05   3.42e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd24B   ccd24A      -6.80e-04   5.49e-06    4.868069e+04  9.344072e-04  -7.201574e-08  -3.782743e-12  
ccd24A   ccd24B      5.14e-04   8.10e-06    4.159671e+04  5.217194e-04  -2.244689e-08  3.250843e-12  
ccd09B   ccd09A      -8.03e-04   6.09e-06    4.395924e+04  -1.466450e-03  2.551152e-07  -1.175802e-11  
ccd09A   ccd09B      3.56e-04   5.76e-06    4.422200e+04  1.469622e-04  -6.468155e-09  4.573219e-12  
ccd10A   ccd09A      4.31e-05   3.80e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd10A   ccd09B      9.74e-05   4.63e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd10B   ccd09B      4.53e-05   2.85e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd10B   ccd10A      -6.13e-04   5.22e-06    4.848351e+04  8.567096e-05  1.628971e-07  -2.254366e-11  
ccd10A   ccd10B      3.81e-04   6.67e-06    4.314500e+04  2.353910e-04  -2.671938e-08  4.970691e-12  
ccd12A   ccd10B      6.68e-05   2.92e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd11B   ccd11A      9.75e-05   8.09e-06    4.230014e+04  -3.903789e-04  4.847455e-08  -5.969791e-13  
ccd11A   ccd11B      2.34e-04   7.34e-06    4.333001e+04  2.654903e-04  -3.853018e-08  5.984682e-12  
ccd12A   ccd11A      4.58e-05   2.76e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd12B   ccd12A      -5.16e-04   4.87e-06    4.062172e+04  -8.936608e-04  6.427286e-08  -7.840033e-13  
ccd12A   ccd12B      1.69e-04   8.61e-06    4.109660e+04  4.530215e-05  8.853301e-09  7.188464e-13  
ccd15B   ccd15A      2.26e-04   7.16e-06    4.129917e+04  -5.830054e-04  7.330805e-08  -9.993544e-13  
ccd15A   ccd15B      3.52e-04   6.02e-06    4.054287e+04  2.880225e-04  -1.733696e-08  2.780847e-12  
ccd16A   ccd15A      3.32e-05   3.36e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd16A   ccd15B      1.19e-04   4.18e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd16B   ccd15B      4.33e-05   3.53e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd09A   ccd16A      2.07e-05   4.53e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd09B   ccd16B      2.43e-05   2.49e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd11A   ccd16B      6.38e-05   2.92e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd16B   ccd16A      -4.93e-04   7.29e-06    4.551762e+04  -4.856586e-04  1.718678e-07  -1.040271e-11  
ccd16A   ccd16B      4.12e-04   7.28e-06    4.254546e+04  7.454177e-04  -1.052059e-07  8.240842e-12  
ccd01B   ccd01A      -6.47e-04   1.07e-05    4.060288e+04  -1.546081e-03  1.996199e-07  -6.782680e-12  
ccd01A   ccd01B      4.24e-04   7.68e-06    4.241862e+04  3.468559e-04  -3.372234e-08  4.094861e-12  
ccd02A   ccd01B      4.80e-05   2.67e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd07A   ccd01A      1.61e-05   2.76e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd02B   ccd02A      1.21e-04   8.62e-06    4.102851e+04  -1.106290e-04  -9.005856e-09  1.776275e-12  
ccd02A   ccd02B      3.12e-04   6.29e-06    4.454614e+04  1.110782e-05  5.331542e-08  5.149784e-13  
ccd03A   ccd02A      3.11e-05   3.43e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd03B   ccd02B      6.03e-05   5.99e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd03B   ccd03A      -6.14e-04   5.53e-06    4.767256e+04  -5.339783e-05  1.963126e-08  -5.269723e-13  
ccd03A   ccd03B      1.57e-04   6.75e-06    4.108025e+04  4.779748e-05  -2.668258e-09  2.166123e-12  
ccd05B   ccd05A      2.93e-04   8.38e-06    4.085550e+04  -1.684165e-04  4.644177e-08  -7.459948e-13  
ccd05A   ccd05B      3.40e-04   4.98e-06    4.310301e+04  5.028621e-04  -6.255596e-08  6.021470e-12  
ccd06A   ccd05A      8.45e-05   2.99e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd06A   ccd05B      1.88e-04   3.05e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd06B   ccd05B      8.10e-05   2.89e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd03A   ccd06B      7.09e-05   3.37e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd06B   ccd06A      -4.57e-04   6.25e-06    4.657035e+04  1.600874e-04  7.129154e-08  -5.802876e-12  
ccd06A   ccd06B      3.82e-04   8.72e-06    4.369817e+04  4.750609e-04  -6.183793e-08  6.949873e-12  
ccd07A   ccd06A      3.07e-05   2.48e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd07B   ccd06B      2.85e-05   2.09e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd01A   ccd07A      3.47e-05   5.38e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd01A   ccd07B      3.01e-05   2.93e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd01B   ccd07B      3.59e-05   3.24e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd07B   ccd07A      -9.67e-04   4.64e-06    4.172172e+04  -1.661753e-03  2.529592e-07  -1.192235e-11  
ccd07A   ccd07B      2.82e-04   4.26e-06    4.998422e+04  5.095241e-04  1.665938e-07  -1.822567e-11  
ccd28B   ccd28A      2.33e-04   5.38e-06    4.425677e+04  4.334732e-05  4.802789e-08  -1.171290e-12  
ccd28A   ccd28B      4.09e-04   5.41e-06    4.320150e+04  2.619608e-04  -1.421727e-08  3.935424e-12  
ccd29A   ccd28A      3.67e-05   4.37e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd29A   ccd28B      1.21e-04   4.65e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd29B   ccd28B      4.17e-05   3.60e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd29B   ccd29A      -3.78e-04   6.66e-06    4.264790e+04  -3.454996e-04  5.499426e-08  2.427540e-14  
ccd29A   ccd29B      5.11e-04   9.22e-06    4.458350e+04  2.697242e-04  1.164680e-08  4.739941e-12  
ccd30A   ccd29A      3.15e-05   5.98e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd30A   ccd29B      8.16e-05   6.34e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd30B   ccd29B      3.91e-05   4.96e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd29B   ccd30A      -1.72e-05   2.74e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd30B   ccd30A      -7.20e-04   6.69e-06    4.376449e+04  -9.961467e-04  2.362914e-07  -1.409822e-11  
ccd30A   ccd30B      3.16e-04   7.53e-06    4.173988e+04  -1.006230e-04  1.059128e-07  -5.259424e-12  
ccd31A   ccd30A      5.16e-05   5.99e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd31A   ccd30B      1.11e-04   3.48e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd31B   ccd30B      3.95e-05   3.21e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd31B   ccd31A      -6.71e-04   4.77e-06    4.537537e+04  -1.937764e-04  1.419847e-07  -1.082217e-11  
ccd31A   ccd31B      4.41e-04   6.18e-06    4.478605e+04  5.308792e-04  -1.066669e-08  2.969986e-12  
ccd35B   ccd35A      2.75e-04   8.23e-06    4.393930e+04  4.850432e-04  -6.022922e-08  6.088015e-12  
ccd35A   ccd35B      3.16e-04   7.62e-06    4.337013e+04  1.981332e-05  5.139773e-09  3.024289e-12  
ccd36A   ccd35A      2.43e-05   4.38e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd36B   ccd35A      7.63e-05   2.39e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd37B   ccd35A      -2.72e-05   3.70e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd37A   ccd35B      -2.60e-05   3.65e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd37B   ccd35B      -2.35e-05   3.41e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd38B   ccd35A      -2.64e-05   5.32e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd38B   ccd35B      -2.65e-05   3.68e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd35A   ccd36B      6.69e-05   2.03e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd36B   ccd36A      -6.90e-04   7.81e-06    4.102332e+04  -1.081565e-03  1.176303e-07  -3.560013e-12  
ccd36A   ccd36B      5.53e-04   7.71e-06    4.113918e+04  4.471957e-04  -4.599712e-09  1.451657e-12  
ccd37B   ccd36A      9.84e-05   5.40e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd36A   ccd37B      -3.68e-05   3.86e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd37B   ccd37A      -9.65e-04   7.49e-06    4.615280e+04  -5.811671e-04  7.648128e-08  -3.620086e-13  
ccd37A   ccd37B      4.51e-04   8.99e-06    4.071915e+04  4.251477e-04  -4.808937e-08  5.336902e-12  
ccd38A   ccd37A      2.06e-05   4.26e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd38B   ccd37A      5.53e-05   3.08e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd38B   ccd37B      2.49e-05   4.05e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd37A   ccd38B      -3.15e-05   5.17e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd38B   ccd38A      -8.39e-04   6.20e-06    4.377215e+04  -5.072515e-04  1.020361e-07  -4.209481e-12  
ccd38A   ccd38B      4.39e-04   7.82e-06    4.048085e+04  2.821421e-04  1.010263e-09  4.684593e-13  
ccd41B   ccd41A      1.52e-04   6.84e-06    4.190875e+04  -6.316020e-04  8.345208e-08  -1.478744e-12  
ccd41A   ccd41B      4.44e-04   1.12e-05    4.588300e+04  1.197172e-04  4.452723e-08  3.903235e-12  
ccd42A   ccd41A      3.94e-05   3.09e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd42B   ccd41A      6.74e-05   2.52e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd42B   ccd41B      2.82e-05   4.15e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd42B   ccd42A      -6.04e-04   7.63e-06    4.525780e+04  -2.582729e-04  1.078027e-07  -5.951368e-12  
ccd42A   ccd42B      4.83e-04   6.59e-06    4.142327e+04  2.942640e-04  1.524157e-08  6.942588e-13  
ccd43A   ccd42A      2.68e-05   3.38e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd43B   ccd42A      6.06e-05   3.96e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd43B   ccd42B      2.53e-05   3.20e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd43B   ccd43A      -8.87e-04   7.44e-06    4.610202e+04  -6.331891e-06  -1.239009e-08  5.486381e-12  
ccd43A   ccd43B      3.76e-04   9.57e-06    4.063302e+04  3.006960e-04  -3.723779e-08  4.231105e-12  
ccd44A   ccd43A      5.43e-05   4.15e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd44B   ccd43B      2.61e-05   3.76e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd44B   ccd44A      -6.56e-04   5.24e-06    4.298461e+04  -1.904655e-03  3.286200e-07  -1.466305e-11  
ccd44A   ccd44B      4.05e-04   7.19e-06    4.000189e+04  6.220029e-05  4.192673e-08  -7.833339e-13  
ccd49B   ccd44B      3.92e-05   3.30e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd49B   ccd49A      4.90e-05   8.13e-06    4.148704e+04  -4.875290e-04  3.473389e-08  1.678255e-12  
ccd49A   ccd49B      3.57e-04   6.21e-06    4.228298e+04  3.462096e-04  -7.900761e-08  8.051282e-12  
ccd50A   ccd49A      2.37e-05   3.73e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd50B   ccd50A      -6.28e-04   6.68e-06    4.438017e+04  -1.045887e-03  1.533865e-07  -4.883584e-12  
ccd50A   ccd50B      1.07e-04   5.77e-06    4.117964e+04  -2.088300e-04  2.722838e-09  2.917113e-12  
ccd47B   ccd47A      9.29e-05   7.59e-06    4.081758e+04  -5.073247e-04  5.997090e-08  -8.734446e-13  
ccd47A   ccd47B      4.27e-04   7.38e-06    4.195402e+04  7.416249e-04  -1.365435e-07  1.161066e-11  
ccd48B   ccd47A      8.12e-05   2.20e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd54A   ccd47B      -3.72e-05   9.87e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd47A   ccd48B      -2.25e-05   2.75e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd48B   ccd48A      -6.09e-04   6.37e-06    4.442098e+04  -7.662088e-04  1.561921e-07  -7.359530e-12  
ccd48A   ccd48B      5.57e-04   9.21e-06    4.192060e+04  3.076270e-04  1.515790e-08  1.770944e-12  
ccd52A   ccd48A      2.30e-05   2.81e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd52B   ccd48B      2.19e-05   2.82e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd54B   ccd48A      7.18e-05   2.50e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd52B   ccd52A      -9.24e-04   7.23e-06    4.184750e+04  -1.354298e-03  1.750528e-07  -6.746239e-12  
ccd52A   ccd52B      4.78e-04   6.99e-06    4.352608e+04  2.368364e-04  2.420803e-08  2.810762e-12  
ccd53A   ccd52A      3.63e-05   3.02e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd53B   ccd52A      1.37e-04   4.40e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd53B   ccd52B      3.88e-05   3.51e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd52A   ccd53B      -1.98e-05   3.80e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd53B   ccd53A      -7.89e-04   5.32e-06    4.514412e+04  -1.811504e-04  6.481036e-08  -4.659942e-12  
ccd53A   ccd53B      4.99e-04   8.99e-06    4.445145e+04  -1.128209e-03  3.922800e-07  -1.895778e-11  
ccd55B   ccd53A      6.31e-05   3.03e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd54B   ccd54A      5.96e-05   6.33e-06    4.034745e+04  -5.017647e-05  -3.638028e-08  3.525615e-12  
ccd54A   ccd54B      3.82e-04   7.08e-06    4.220941e+04  2.805845e-04  -5.511998e-08  7.743376e-12  
ccd55A   ccd54A      8.36e-05   4.31e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd55B   ccd54B      1.93e-05   8.41e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd55B   ccd55A      -7.43e-04   5.70e-06    4.246820e+04  -1.446753e-03  2.022911e-07  -8.806607e-12  
ccd57B   ccd57A      1.16e-04   6.10e-06    4.296856e+04  -4.358962e-04  4.313735e-08  -5.694893e-13  
ccd57A   ccd57B      4.37e-04   9.55e-06    4.249676e+04  1.761828e-04  2.223526e-08  4.242898e-13  
ccd58A   ccd57A      5.58e-05   3.80e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd58B   ccd57A      1.63e-04   3.04e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd58B   ccd57B      4.77e-05   3.35e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd58B   ccd58A      -6.66e-04   6.20e-06    4.063899e+04  -1.240751e-03  1.375953e-07  -3.231629e-12  
ccd58A   ccd58B      5.06e-04   7.26e-06    4.102077e+04  5.343781e-04  -4.554472e-08  4.984779e-12  
ccd59A   ccd58A      2.87e-05   6.46e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd59B   ccd58B      3.04e-05   2.93e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd60A   ccd58A      -2.59e-05   5.79e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd59B   ccd59A      -9.93e-04   5.50e-06    4.141155e+04  -1.411827e-03  1.352100e-07  -3.835709e-12  
ccd59A   ccd59B      3.35e-04   7.62e-06    4.397818e+04  1.114668e-04  3.897544e-08  1.247212e-12  
ccd60A   ccd59A      3.07e-05   3.58e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd60B   ccd59B      3.42e-05   4.03e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd61B   ccd59A      -2.48e-05   1.96e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd58A   ccd60A      -2.41e-05   3.45e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd60B   ccd60A      -6.86e-04   5.97e-06    4.081500e+04  -1.286447e-03  8.712351e-08  -1.448095e-12  
ccd60A   ccd60B      4.48e-04   5.81e-06    4.010889e+04  5.325449e-04  -2.397624e-08  1.186962e-12  
ccd59B   ccd61A      -2.31e-05   9.18e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd61B   ccd61A      1.12e-04   8.83e-06    4.195796e+04  -7.125977e-04  1.259627e-07  -4.557482e-12  
ccd61A   ccd61B      3.33e-04   1.56e-05    4.154934e+04  3.956827e-04  -8.381924e-08  7.662476e-12  
ccd62A   ccd61A      2.91e-05   9.27e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd62B   ccd61A      -2.73e-05   1.11e-05    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd62B   ccd61B      4.35e-05   1.02e-05    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd61B   ccd62B      2.01e-05   1.77e-06    1.000000e+10  0.000000e+00  0.000000e+00  0.000000e+00  
ccd62B   ccd62A      -7.12e-04   4.79e-06    4.795145e+04  -5.917578e-04  1.465943e-07  -8.506643e-12  
ccd62A   ccd62B      1.04e-04   4.65e-06    4.804204e+04  4.665994e-04  -1.448564e-07  9.934450e-12  

I googled but didn’t find the definitions of the columns. I’m assuming that they are a non-linear fit to the crosstalk, and http://www.ctio.noao.edu/noao/content/decam-known-problems implies that they used to have such an effect. I’m not sure if that was before they started correcting for quadratic non-linearity in the readout electronics

Non-linearity corrections should be there (I wrote it), and it’s supported in camGeom. @SimonKrughoff do you know anything about this?

The notes at http://www.ctio.noao.edu/noao/content/decam-known-problems imply that it used to be non-linear but now isn’t, so we’ll need to version camGeom – we can do this as an obs_decam version but as we know it’d be better in the nbutler.

We should be able to do this in the Old Butler; that’s one of the things that I think you wanted pushed after registry-less repositories (“more important than […] improvements to versioning”).

It’s 249 xtalk coefficients for 124 amps (62 chips, 2 amps each), so there are some non-negligible inter-chip cross-talk.

It isn’t the highest priority because we can version obs_decam if we must (ignoring Von Neumann’s strictures)

Looks to me like non-linearity corrections for HSC are done here, not in general-purpose ISR code: https://github.com/lsst/obs_subaru/blob/3452c1f7ab32105cbe465c4e5806f6da42d457fc/python/lsst/obs/subaru/isr.py

Right, just like crosstalk. So this needs to be copied/cherry-picked to obs_decam and we need to think about how to make this more generic or more easily extended or more easily plugged into. “Use this external cross-talk module from HSC in Decam”. Or something.

I noticed you specifically mentioned the Community Pipeline processing. Is the DES ISR different? Substantively or just in implementation?

It’s very similar. Actually the CP is a subset of the DESDM processing software. But DESDM only processes their own data, while the CP processes all the community data (and the documentation seems to be a bit better).

We do use the fringe code for HSC (it’s needed for y-band). It has been in ip_isr for ages now.

That’s great! Hopefully it’ll work for DECam as well.

Sorry for missing this conversation. Evidently the discourse emails got lost in the noise.

Regarding non-linearity, there was an implementation of this in ISR done long ago, but I don’t believe it ever satisfied all the requirements, thus the re-implementation in obs_subaru.

As far as inter-chip crosstalk goes, we don’t currently have a defined way to do this. I think we can probably work around it by getting relevant images from the butler inside the isr routine. From a very quick look, it seems that any amp is only affected by one other chip.

Great.

Yes, I think you are right about the the crosstalk. From the coefficients it just seems like one other (neighboring?) chip is affected.

I/O in the task code (and therefore passing in blobs such as dataRefs) is exactly the pattern I’m trying to move away from. In this short run it might be pragmatic though.

I agree that we should be moving away from that pattern, but I’m not sure how to make headway without having to produce a new crosstalk design. Maybe it’s easy. I haven’t had a chance to look.

I’ve been wondering if there’s a way to do cross-talk without having to pull in every image for every chip (in reality a chip only affects a small number of other chips). Only the pixels with lots of flux actually have a cross-talk effect. So I’m wondering if it would be possible to pull out all of the “bright” pixels (above a few thousand ADU or something like that) and put it in a smallish image/array/file that, of course, remembers the (x,y) coordinates of the pixels. Then you run through all the chips once and create these “bright pixel” files. When you run cross-talk on an individual chip you load in all of the bright pixels from all chips (which should not be very memory intensive), and remove the cross-talk just from those pixels (from chips that have non-negligible cross-talk coefficients). Does this sound doable/reasonable? Of course it breaks down in crowded fields.

There is currently the concept of a “heavy” footprint in the stack. This is essentially the minimum set of bounding boxes for a source and the pixels associated. I think that’s what you need.

That being said, I don’t think it would be hard to load the image you need inside the cross-talk method. It’s not very efficient, but I think the efficient mechanism needs a new design before we can do it in a non-hacky way.