Документ взят из кэша поисковой машины. Адрес оригинального документа : http://xmm.vilspa.esa.es/docs/documents/Appendix/omcal_oct00/omcal_alice_cm_boresight.pdf.gz Дата изменения: Mon Nov 13 13:45:54 2000 Дата индексирования: Sat Dec 22 15:26:56 2007 Кодировка: Поисковые слова: южная атлантическая аномалия

OM Calibration meeting MSSL 10th/11th October 2000 Alice Breeveld

BORESIGHT
Closely associated with distortion issues So far First measurements suggested we were off by ~ 2' AHF (attitude history files) contain RA, Dec and PA as the startracker sees it. The SIAM matrix offsets startracker in X,Y and angle so that we get the prime target object in the middle of the prime instrument's FOV. /Changes in SIAM matrix move target relative to our boresight. /Offset from startracker remains constant. Made table of OM boresight vs startracker and target, wrt prime instrument. Procedure for making table: Used LMC map throughout. · Matched sources with centroided detector coordinates. (starlist) · Put this and distortion map into Rudi's radec2pix.tpt. · Boresight routine then calculates pixel positions and adjusts boresight to the minimum moment. · Then, add startracker position as if it were a source Х startracker position in detector coordinates.


Sources of error: O O O O O Startracker position error - probably biggest. Star matching - errors in catalogue positions, and errors in centroiding of OM data. Distortion map - Moment(distance) gives a measure of the map error Startracker position - when insert this as a 'star' its false position affects fit (this is a tiny affect) Conflict between coordinate systems.

summary of startracker positions: Prime same same E3 E3 E3 E3 R1 R1 E3 E3 E3 O1 E3 E3 O1 R1 X 945.26 964.96711 947.67662 949.67937 961.23319 957.52640 955.88311 955.98446 953.66081 966.41489 958.49717 958.37267 960.60154 955.84500 959.68780 948.96 Y 793.82 795.80402 805.75161 806.07093 815.3387 813.83869 815.10668 815.18342 812.64111 815.58057 813.47293 810.61260 806.51444 807.33473 812.09296 818.95

mean 955.6+/-5.8, 809+/-6.8 potential error on boresight therefore = +/- 9 pixels (= +/- 4.5 arcs) Questions q What was the upshot of all that discussion on common boresights? q Are targets in the centre of our FOV when we are prime instrument? or are we offsetting them to get out of worst straylight. q What is accuracy needed for SAS? Further work


q Do I need to do any more? q Should I repeat this work with different filters?

Pictures Boresight of other instruments and OM


OM boresight compared with startracker boresight

Field Rev Prime No. objects

Intended boresight (from POS, or commissioning plan) Measured boresight (from boresight.pro) AHF boresight (from AHF file) Coords of startracker pointing moment(distance)

[moment(distance) = mean of calc. position ­ measured detector position]

RA Dec PA ----------------------------------------------------EXO Int. 17 Meas. same AHF 24 st pos Int. 17 Meas. same AHF 45 st pos 19 same

RA

Dec

117.10208 -67.75 174.4 07:48:25.00 -67:45:00 117.02549 -67.763141 174.471 07:48:6.12 -67:45:47.30 ? 945.26 793.82 moment(dist) = 1.4 187.2791 2.0525 112.1 12:29:07.00, +02:03:09.0 187.27479 2.0210082 112.08 12:29:05.95 +02:01:15.63 ? 964.96711 795.80402 moment(dist) = 3.1 07:48:25.00 -67:45:00

3C273

EXO

Int. 117.10208 -67.75 ?? Meas. funny image Int. Meas. AHF st pos Int. Meas. AHF st pos Int. Meas. AHF stpos 84.237 -69.2297 84.154401 -69.222376 84.239 -69.2300 947.67662 805.75161

LMC 21 E3 238 Hickson 23 E3 13

212.9 05:36:57.00 -69:13:47.0 212.97 05:36:37.1 -69:13:20.55 212.90 05:36:57.48 -69:13:48.1 moment(dist) = 1.86

32.4104 -10.1469 250.7 02:09:38.5 -10:08:49.0 32.3901 -10.122 250.716 02:09:33.62 -10:07:21 32.4093 -10.147 250.705 02:09:38.23 -10:08:49.5 949.67937 806.07093 moment(dist) = 2.4 47.979 -76.6642 276.9 03:11:55 48.015478 -76.660360 276.152 03:12:3.714 48.0380 -76.6893 276.131 03:12:09.11 961.23319 815.3387 moment(dist) = 1.91 -76:39:51 -76:39:37.3 -76:41:21.4

PKS0312 off6 34 E3 21

EXO Int. -67.740733 215.73 E3 AHF 22 stpos

117.104 -67.7500 214.4 07:48:25.0 -67:45:00.0 07:48:25.5 -67:44:26.6 117.18 -67.7502 215.689 07:48:43.35 -67:45:00.8 957.52640 813.83869 moment(dist) = 1.27

37

Meas. 117.106


PKS0558 45 R1 30 815.18342 Hy off1 Int. 49 E3 9 Hy off 3 49 E3 24 V2416 SGR 52 O1 17 LMC X-3 66 E3 21 Lockman 70 E3 16 Lockman 71 E3 19

Int. 89.9458 Meas.(1) 89.95 AHF 89.9794 stpos(1) 955.88311 Meas.(2) 89.956 moment(distance) =

-50.447 256.55 05 59 47.0 -50 26 51.0 -50.440852 257.9 05 59 49.5 -50 26 27.0 -50.4666 257.8 05 59 55.05 -50 27 59.7 815.10668 moment(distance) = 1.752 -50.440860 257.90 05 59 49.5 -50 26 27.0 1.746

stpos(2) 955.98446

67.7958 18.1967 262.5 04 31 11.0 +18 11 48.0 Meas. 67.802011 18.201786 264.17 04 31 12.4 +18 12 6.4297 AHF 67.8147 18.1743 264.233 04 31 15.53 +18 10 27.5 stpos 953.66081 812.64111 moment(dist) = 4.7 Int. Meas. AHF stpos Int. Meas. AHF stpos Int. Meas. AHF stpos Int. Meas. AHF stpos Int. Meas. AHF stpos 67.962 17.8633 262.66 04 31 67.969268 17.868232 264.40337 04 31 67.9801 17.8409 264.411 04 31 966.41489 815.58057 moment(dist) 51.0 +17 51 48.0 52.62 +17 52 5.63 55.22 +17 50 27.4 = 1.3

269.317 -21.6914 090.18 17 57 16.03 -21 41 29.0 269.31534 -21.687944 090.180 17 57 15.6 -21 41 16.5 269.306 -21.6591 90.1999 17:57:13.48 -21:39:32.7 958.37267 810.61260 moment(dist) = 1.83 84.7333 -64.0839 302.18 05 38 56.0 84.752695 -64.084565 303.88647 05 39 0.64 84.7327 -64.1130 303.917988 05 38 55.85 958.49717 813.47293 moment(dist) = 1.6 163.179 57.4800 311.33 10 52 163.19532 57.479488 313.04556 10 52 163.171 57.4519 313.03849 10 52 960.60154 806.51444 moment(dist) 163.18 163.20 163.17 955.845 -64 05 02.0 -64 05 04.4 -64 06 46.7

43.00 +57 28 48.0 46.87 +57 28 46.15 41.01 +57 27 06.9 = 1.31

57.4831 309.91 10:52:44.2 +57:28:59.0 57.482 311.62597 10 52 48.09 +57 28:56.1 57.4544 311.647 10:52:42.40 +57:27:16.0 00 807.33473 moment(dist) = 1.21

Abell 2690 88 O1 17 Abell 1795 100

Int. 0.1250 -25.125 060.98 00 00 30.0 -25 07 30.0 Meas. 0.1217 -25.122475 60.988280 0 0 29.2 -25 7 20.9 AHF 0.0982 -25.1015 61.006846 00 00 23.59 -25 06 05.5 stpos 959.68780 812.09296 moment(dist) = 1.04 Int. 207.221 26.5922 288.69 Meas. 207.22846 26.593663 290.12682 13 48 53.0 13 48 54.8 26 35 32.0 26 35 37.1


R1 17

AHF 207.228 stpos 948.96

26.5642 290.157 13 48 54.74 818.95 moment(dist) = 1.38

+26 33 51.3