Chandra Aspect Operations

Evaluation of use of 8x8 image data for guide stars during science

Summary

During November and December 2012, a series of image readout tests were commanded. In each test, a pair of ERs were commanded with identical star catalogs (to each other) except one catalog in each pair was commanded with 8x8 image readout windows on guide stars and the other with 6x6 image readout windows on guide stars. These test data are intended to be used to quantify the potential benefits of using 8x8 mode on guide stars during science observing.

Data

7 pairs of observations were commanded. In each pair, the 6x6 data collection followed the "nominal" 8x8 ER.

Analysis

Data from each observation was processed using the standard ground aspect pipeline. Additionally, the first 5ks of each observations has been run with the "worst" (in this case, the star with the largest RMS on the centroid Z residuals) slot dropped. Centroid residuals for each star were determined vs the the "all star" aspect solution and the "with worst slot dropped" aspect solution using a development V&V tool. These residuals are plotted below. The stars from an observation pair have been plotted with a shared symbol.

Notes

An ~8.75 mag star jumps out of the stddz plots (the red and blue squares at 8.75mag) due to the size of the difference of the residuals, especially on the "dropped worst star" version of the plot. I took a look at the raw ACA data for that star (slot 0) but really, everything looks so noisy in the 8x8 data that it is hard to notice trends.

I experimented with processing the 8x8 data with the outer pixels all set to zero, but this did increase all of the star RMS values. More work to be done there, but hopefully that indicates that more data is not bad and the bad pixel detection and gaussian centroiding are more effective than just throwing away data.

Other Data

Image status flags ( and that's the percentage of the data for the obsid with flag set and is log scaled for def_pix and mult_star).

Raw data including the residuals calculated against the aspect solution with all stars

6x6 obs 8x8 obs m slot agasc6 agasc8 mag6 mag8 stddy6 stddy8 stddz6 stddz8 def_pix6 def_pix8 ion_rad6 ion_rad8 mult_star6 mult_star8
54108 54110 o 0 379852088 379852088 6.60 6.59 0.05 0.07 0.05 0.08 0.000 0.000 0.079 0.000 0.000 0.000
54108 54110 o 1 379853296 379853296 9.22 9.20 0.09 0.09 0.09 0.08 8.969 7.765 0.751 0.459 0.316 0.125
54108 54110 o 2 379856632 379856632 8.42 8.40 0.06 0.08 0.07 0.06 0.000 0.000 0.158 0.083 0.079 0.000
54108 54110 o 3 380371504 380371504 8.00 7.97 0.05 0.07 0.08 0.09 0.000 0.000 0.119 0.083 0.000 0.000
54108 54110 o 5 380257064 380257064 10.22 10.19 0.20 0.19 0.13 0.13 6.559 4.759 1.580 2.108 7.270 6.846
54108 54110 o 6 379863584 379863584 8.44 8.41 0.06 0.06 0.07 0.08 0.158 0.000 0.316 0.083 0.000 0.042
54108 54110 o 7 379850456 379850456 10.16 10.12 0.18 0.19 0.13 0.18 12.564 11.918 2.805 2.672 8.534 6.178
54116 54118 ^ 0 162794432 162794432 8.55 8.52 0.08 0.10 0.06 0.12 0.000 0.000 0.312 0.040 0.000 0.040
54116 54118 ^ 1 162794480 162794480 8.25 8.23 0.09 0.14 0.08 0.12 0.078 0.000 0.468 0.040 0.078 0.000
54116 54118 ^ 2 162797928 162797928 8.48 8.46 0.08 0.13 0.07 0.15 0.000 0.000 0.351 0.079 0.000 0.000
54116 54118 ^ 3 162799224 162799224 9.25 9.23 0.11 0.12 0.15 0.12 3.943 3.639 0.976 0.435 0.351 0.119
54116 54118 ^ 4 162792800 162792800 10.31 10.23 0.18 0.27 0.20 0.20 32.325 21.835 5.895 3.758 3.592 2.176
54116 54118 ^ 6 162799088 162799088 10.52 10.42 0.31 0.36 0.26 0.47 19.988 22.488 2.752 3.283 30.978 24.723
54116 54118 ^ 7 162272096 162272096 10.50 10.41 0.26 0.18 0.13 0.17 8.823 7.911 1.991 2.017 38.532 44.106
54123 54125 s 0 382206296 382206296 8.85 8.79 0.11 0.08 0.08 0.16 0.039 0.000 0.273 0.297 0.156 0.127
54123 54125 s 1 382223336 382223336 8.07 8.06 0.07 0.09 0.06 0.09 0.000 0.000 0.078 0.212 0.000 0.000
54123 54125 s 2 382223440 382223440 9.17 9.16 0.11 0.10 0.12 0.09 11.847 13.452 1.208 0.721 0.117 0.127
54123 54125 s 3 382223608 382223608 7.73 7.72 0.06 0.07 0.06 0.08 0.000 0.000 0.078 0.085 0.000 0.000
54123 54125 s 4 382220968 382220968 10.14 10.10 0.21 0.32 0.17 0.25 12.042 13.325 3.936 1.952 0.779 0.255
54123 54125 s 5 382223232 382223232 9.98 9.97 0.11 0.13 0.11 0.13 8.145 1.358 1.052 0.891 9.392 8.530
54123 54125 s 6 382213440 382213440 10.25 10.22 0.14 0.18 0.16 0.19 0.000 0.000 0.468 0.255 4.988 4.456
54123 54125 s 7 382223448 382223448 9.82 9.81 0.09 0.10 0.11 0.11 10.990 8.912 1.208 1.040 1.052 0.637
54129 54131 > 0 436209240 436209240 7.72 7.73 0.07 0.07 0.06 0.05 0.000 0.222 0.066 0.049 0.000 0.025
54129 54131 > 1 436220392 436220392 8.35 8.37 0.06 0.05 0.07 0.07 0.000 0.025 0.231 0.123 0.033 0.000
54129 54131 > 2 436231552 436231552 8.55 8.57 0.06 0.05 0.07 0.06 0.000 0.000 0.198 0.321 0.099 0.173
54129 54131 > 3 436231744 436231744 8.00 8.01 0.06 0.06 0.07 0.07 0.000 0.000 0.165 0.148 0.000 0.000
54129 54131 > 4 436233528 436233528 10.01 10.03 0.14 0.15 0.15 0.18 10.422 14.305 1.682 1.406 0.264 0.296
54129 54131 > 5 436210824 436210824 10.28 10.33 0.17 4.29 0.16 9.54 0.264 5.895 0.594 0.271 4.469 7.301
54129 54131 > 6 436214776 436214776 10.91 10.94 0.63 0.28 0.31 0.20 17.150 9.989 2.474 2.022 27.606 19.559
54129 54131 > 7 436208128 436208128 10.22 10.24 0.16 0.14 0.17 0.14 0.594 1.381 1.352 1.480 9.070 5.525
54150 54152 * 0 5774184 5774184 6.89 6.88 0.08 0.10 0.09 0.11 0.000 0.000 0.057 0.071 0.000 0.000
54150 54152 * 1 5776104 5776104 8.97 8.94 0.07 0.09 0.08 0.09 0.000 0.071 0.341 0.321 0.256 0.071
54150 54152 * 2 5775872 5775872 8.98 8.96 0.15 0.10 0.09 0.07 0.000 0.000 0.312 0.143 0.199 0.178
54150 54152 * 3 5778000 5778000 10.07 10.03 0.21 0.16 0.19 0.19 7.415 2.959 1.420 0.642 0.312 0.285
54150 54152 * 4 5771048 5771048 10.15 10.12 0.13 0.19 0.15 0.19 0.085 0.143 0.483 0.357 3.608 2.496
54150 54152 * 6 5768840 5768840 10.09 10.06 0.10 0.10 0.20 0.22 1.591 0.071 1.222 0.677 7.358 7.701
54150 54152 * 7 5771992 5771992 7.27 7.26 0.07 0.09 0.08 0.10 0.000 0.000 0.057 0.000 0.000 0.000
54163 54164 < 0 376065400 376065400 8.64 8.61 0.04 0.05 0.07 0.07 0.000 0.041 0.112 0.816 0.112 0.245
54163 54164 < 1 376066648 376066648 7.73 7.72 0.05 0.09 0.06 0.08 0.000 0.000 0.056 0.327 0.000 0.000
54163 54164 < 2 376582192 376582192 8.32 8.30 0.04 0.07 0.06 0.06 0.000 0.000 0.056 0.571 0.000 0.122
54163 54164 < 3 376599248 376599248 9.12 9.11 0.06 0.08 0.09 0.10 3.314 4.612 0.674 1.429 0.000 0.367
54163 54164 < 4 376571376 376571376 10.50 10.49 0.16 0.21 0.23 0.25 2.977 3.878 0.281 1.714 14.153 14.878
54163 54164 < 5 376587064 376587064 10.15 10.10 0.12 0.19 0.21 0.17 0.000 0.082 0.112 1.469 17.720 16.531
54163 54164 < 6 376596416 376596416 10.34 10.27 0.15 0.19 0.12 0.18 0.000 3.224 0.225 1.429 14.238 16.224
54163 54164 < 7 376065352 376065352 10.12 10.08 0.14 0.18 0.18 0.21 0.000 0.122 0.225 1.265 0.449 1.510
54165 54166 x 0 5380208 5380208 8.52 8.50 0.07 0.05 0.07 0.11 0.000 0.000 0.383 0.071 0.070 0.000
54165 54166 x 1 5380568 5380568 7.68 7.67 0.04 0.06 0.07 0.10 0.000 0.000 0.383 0.071 0.000 0.000
54165 54166 x 2 5381168 5381168 8.36 8.32 0.05 0.05 0.07 0.10 0.000 0.000 0.383 0.143 0.070 0.000
54165 54166 x 3 5776464 5776464 8.67 8.65 0.09 0.07 0.06 0.11 0.000 0.000 0.523 0.143 0.279 0.000
54165 54166 x 4 5382264 5382264 10.41 10.35 0.15 0.23 0.17 0.30 0.383 0.107 1.011 0.250 5.924 6.821
54165 54166 x 5 5509168 5509168 10.36 10.31 0.13 0.14 0.17 0.21 15.752 12.071 3.833 2.357 25.545 32.214
54165 54166 x 6 5379880 5379880 10.06 10.04 0.08 0.11 0.13 0.16 0.139 0.000 0.854 0.143 21.467 20.857
54165 54166 x 7 5382288 5382288 10.06 10.00 0.15 0.10 0.14 0.14 17.181 12.714 4.286 4.179 8.747 12.321


Last modified:01/16/13


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