Commissioning of AOT PHT51 for C200 in C_160 filter 14/10/97 U. Klaas 0 Summary The analysis presented here has shown that the polarisation AOT PHT51 with C200 and the C_160 filter fulfills the following conditions: 1) All necessary infrastructure is available: a) A PGA like interface is provided by the PHT AOT simulator program PHTAOT. This program produces directly the COB file which has to be converted into the deliverable COIF via the CUS set-up on the PIDT calibration account. b) Special pointing requests (pixel offsets) can be handled by PIDT tools. c) Signal processing can be done using PIA. d) A FORTRAN program (POLCALC_2) is available for the derivation of all polarisation values incl. uncertainties. This can eventually be implemented into PIA. 2) The currently implemented observing sequence with a minimum measurement time of 128 s per individual measurement and a minimum of two repetitions of a full polariser cycle proved to provide very stable signals. The overall S/N ratios of the measurements have been assessed, incl. the one of the isolated source flux depending on the source-to-background contrast. For the total flux S/N ratios of 100 - 200 are typical, for the covered source-to-background contrasts S/N ratios of 30 to 80 were found. Additional polarisator cycles and future transient corrections will improve the accuracy further. 3) The instrumental polarisation of C200 has been determined for each pixel with an accuracy of about 0.5% in degree and 2 deg in angle. 4) Several commissioning measurements on polarised and unpolarised sources in the brightness range of 2 to 3 Jy were performed and evaluated to check for the achievable accuracy and overall consistency. With the current set-up 2 Jy point sources with 5% polarisation on a 1Jy/beam background, achieving a S/N of 80, can be measured with 3 sigma confidence. To achieve the maximum source-to-background contrast centering of a point source on one pixel is highly recommended (increase by about a factor of 4, but observations have to become fixed time). For negligible background 3% polarisation with 3 sigma confidence are feasible. 20% polarised sources can be measured with a 3 sigma confidence level down to a source-to-background ratio of 0.4. 5) The time request for the C200 PHT51 polarisation mode is the following: TDT OTT 2 cycles 1331 s 1137 s 3 cycles 1737 s 1543 s 4 cycles 2143 s 1949 s We therefore conclude that the C200 FIR polarisation mode (restricted to the C_160 filter) is working and recommend to release it to the observer. 1 Introduction This report extends the previous report "Commissioning of P51: C200 Polarisation Observations of 3C 279" from 18/11/96, as considerably more measurements have been used for the analysis and more aspects could be addressed. This comprises 1) a detailed assessment of the instrumental polarisation from a data set of measurements of unpolarised sources; 2) the reproducibility of signals in the polariser cycles and resulting S/N ratios; 3) the impact of the background subtraction on the final accuracy, depending on the source-to-background contrast; 4) a detailed error propagation, incl. computation of maximum errors; 5) derivation of the polarisation for the polarised source 3C 279 for two epochs. 2 Implementation The observations were implemented using the PHT AOT simulator program PHTAOT which provides a user interface similar to PGA. PHTAOT produces automatically a COB file which can be converted into a COIF file for import into the Mission Data Base using the CUS. The COB file can contain a whole proposal consisting of up to 99 IONs. For simplification of the measurement analysis, the cold read-out electronics setting for the final FCS measurement in the observation sequence is forced to have the same set-up as the sky measurement. This is implemented in PHTAOT V4.4. 3 Measurement Strategy For the commissioning measurements always the same observational set-up was used. All measurements are done in STARING MODE. This consisted of 2 cycles through the three polarisers, a normal photometric measurement followed by an FCS measurement of the same length. The integration times were set to 128 s for each individual measurement, thus giving 256 s integration time per polariser. The 128 s measurement time proved to be absolutely sufficient to achieve stable signals. Stabilisation is achieved within the first 30 to 40 s, so that 128 s measurement time are recommended to be maintained for future observations. To increase the statistics of the measurement reproducibility, and hence the basic signal uncertainty, more than 2 cycles can be considered. A minimum measurement time of 256 s per polariser cycle split into two polariser cycles is recommended. 4 Signal Processing PIA was used to process the ERD to average signals per chopper plateau (SCP). The processing included default deglitching on read level, first order polynomial fit, default deglitching on signal level, default dark subtraction, and weighted average signal per measurement. So far no attempt has been made to correct some measurements for signal dependence on reset interval, but the difference between an on-target and its corresponding off-target measurement is a factor of 2 at most so that only minor correction effects are expected. Also no attempt has been made to subtract an orbit dependent dark signal level. Also no transient correction was applied. 5 Polarisation Calculation The formulae used for derivation of the polarisation values were checked to be consistent with the description of an imperfect polariser as given by formula (20) in K. Serkowski, 1962, "Polarisation of Starlight" in Advances in Astronomy and Astrophysics, Zdenek Kopal (ed.), Academic Press, p. 289: The Stokes parameters of linear polarisation are derived from the three measured intensities: I = 1/3 * (I(0) + I(120) + I(240)) (1) U = 1/(sqrt(3) * P') * (I(240) - I(120)) (2) Q = 1/(3 * P') * (2*I(0) - I(120) - I(240)) (3) From measurements in the ground calibration facility using a pre-polariser it was deduced that the actual orientations of the polarisers are within 1 deg of their nominal orientation. We therefore used the nominal orientations in order to make the formulae simpler. The effects by slight miss-orientation of the polarisers are considered as negligible. This will be followed up in future error analysis work. P' is the polariser efficiency. We assume, according to the statement by the manufacturer (MPIfR), that the polariser efficiency is the same for all 3 polarisers. From measurements in the ground calibration facility the polariser efficiency was derived to be around 90%. We apply an uncertainty of 3%. Polarisation degree and angle are calculated via the formulae: P = 1/I * sqrt(U^2 + Q^2) (4) Theta = 1/2 * arctan(U / Q) (5) Theta is defined in the range 90 deg > Theta > -90 deg. For averaging negative angles are handled as 180 deg + angle, e.g. -89 deg is equivalent to +91 deg. Quoted angles are w.r.t. the S/C y-axis coordination system; for the orientation on the sky the angle of the y-axis orientation has to be added. It can be seen that the value of the polarisation efficiency is only affecting the polarisation degree, but not the polarisation angle, as it cancels out in the quotient U/Q. For the polarisation degree it is only a scaling factor with P ~ 1/P'. Sky background subtraction is performed by subtracting the off-target Stokes parameters from the on-target Stokes parameters: I = I(on) - I(off) U = U(on) - U(off) Q = Q(on) - Q(off) (6) Correction for instrumental polarisation of sky measurements was done on the level of normalised Stokes parameters: u = U/I - P(inst) * sin(2*Theta(inst)) (7) q = Q/I - P(inst) * cos(2*Theta(inst)) (8) The error calculation included both Gaussian error propagation (square root of sum of squared partial derivatives) providing a 1 sigma error and maximum error propagation (sum of partial derivatives). The latter one was done to check the consistency of results of measurements of both polarised and unpolarised sources. From formula (4) above it can be seen that even in the case of an unpolarised source P is > 0, if Q and U are not both exact zero. In the case of small S/N ratios the so-called debiased polarisation degree can be used which takes the error into account (Wardle J. & Kronberg P., 1974, ApJ 194, 249): P(db) = sqrt(P^2 - dP^2) (9) All calculations, including the error calculation were implemented in a FORTRAN program (POLCALC_2). The detailed formulae used for this program will be given elsewhere. The program can be used both for derivation of instrumental polarisation and sky polarisation, provided the input signal files are set up accordingly (instrumental polarisation derivation MUST have set the background signals equal to zero). 6 Instrumental Polarisation Instrumental polarisation for the C_160 filter was derived from a data set of 7 observations with two independent measurements each. Log of observations: no. rev. target comment -------------------------------------------------------------- 1 253 3C 279 off 3C 279 background 2 440 HR 5340 off alpha Boo background 3 440 HR 5340 alpha Boo star 4 583 3C 279 off 3C 279 background 5 587 HR 5340 off alpha Boo background 6 587 HR 5340 alpha Boo star 7 587 HR 5340 "pix 3" alpha Boo star centred on pixel 4 (!) -------------------------------------------------------------- The data sheets of these measurements are contained in Appendix B. The resulting instrumental polarisation was obtained by computing the weighted mean, using the invididual uncertainties as weighting factors. The currently best values for C-160 instrumental polarisation are: pixel P(inst) dP(inst) Theta(inst) dTheta(inst) [%] [%] [deg] [deg] ------------------------------------------------------- 1 4.94 0.25 -57.09 0.82 2 5.50 0.30 +87.65 1.13 3 6.10 0.31 -39.46 0.81 4 3.36 0.25 -76.47 1.75 ------------------------------------------------------- The quoted errors are the standard deviations of the mean. For the error calculation in POLCALC_2 we have used the 2 sigma values. It is not anomalous that the instrumental polarisation is different for the 4 C200 pixels, as they are individual elements with each having its own stressing mechanism, bias voltage, and field lens. Future background measurements will be used to increase the data base of instrumental polarisation measurements. 7 Signal uncertainties of polarisation measurements The signal uncertainties have been derived per pixel from the reproducibility of the measurements of the two cycles in all three polariser settings. dI(0) = dI(120) = dI(240) = 1/sqrt(3*Ncyc-1) * sqrt(SUM(i=1..Ncyc) (I(0)i - I(0)av)^2 + SUM(i=1..Ncyc) (I(120)i - I(120)av)^2 + SUM(i=1..Ncyc) (I(240)i - I(240)av)^2) For the background subtracted source flux the error is: dI(source) = sqrt(dI(on)^2 + dI(off)^2) In the following we list the average signals, the derived uncertainties and the resulting signal-to-noise ratios for the 3 measurements on the polarised source 3C 279 (see Appendix A, entries 1 -3 for full data sheets): 1) 3C 279, rev. 253, centering on array average signals of all polariser cycles: pixel pol. orientation source signal background signal [deg] [mV/s] [mV/s] 1 0 198.2065 172.2655 1 120 208.3895 180.4570 1 240 206.9215 170.0710 2 0 160.1560 131.4115 2 120 166.4975 133.3970 2 240 180.5535 138.4150 3 0 171.0375 136.0825 3 120 169.3010 137.6645 3 240 169.6510 128.1215 4 0 142.1770 116.1130 4 120 141.2890 116.9510 4 240 149.7650 117.4665 standard deviation of source and background signal pixel dsig dback [mV/s] [mV/s] 1 0.9318 0.7536 2 1.2711 1.5816 3 0.8251 0.8665 4 0.6560 0.6367 S/N ratios for on- and off-position and source and source-to-background contrast pixel S/N_on S/N_off S/N_sour source/back contrast 1 219.48 231.26 25.24 0.1735 2 133.01 84.98 17.08 0.2579 3 206.03 154.60 30.12 0.2690 4 220.14 183.53 30.16 0.2359 2) 3C 279, rev. 583, centering on array average signals of all polariser cycles: pixel pol. orientation source signal background signal [deg] [mV/s] [mV/s] 1 0 117.7200 92.5026 1 120 127.3140 97.3398 1 240 120.4140 91.1083 2 0 104.7205 75.8560 2 120 114.6005 80.4989 2 240 119.0265 82.1808 3 0 101.0540 74.4141 3 120 103.7135 75.0240 3 240 96.8411 70.0167 4 0 88.1726 63.1605 4 120 92.6513 67.0776 4 240 93.1306 66.9127 standard deviation of source and background signal pixel dsig dback [mV/s] [mV/s] 1 2.4382 0.3277 2 2.5630 1.4558 3 1.1938 0.4353 4 1.0088 0.8651 S/N ratios for on- and off-position and source and source-to-background contrast pixel S/N_on S/N_off S/N_sour source/back contrast 1 49.96 285.80 11.45 0.3008 2 44.00 54.62 11.29 0.4184 3 84.22 168.04 21.55 0.3744 4 90.52 75.96 19.26 0.3896 3) 3C 279, rev. 583, centering on pixel 4 average signals of all polariser cycles: pixel pol. orientation source signal background signal [deg] [mV/s] [mV/s] 1 0 112.0850 92.5026 1 120 123.9030 97.3398 1 240 115.1030 91.1083 2 0 95.2727 75.8560 2 120 99.3865 80.4989 2 240 101.4010 82.1808 3 0 88.7044 74.4141 3 120 90.9005 75.0240 3 240 84.0895 70.0167 4 0 156.5070 63.1605 4 120 171.0235 67.0776 4 240 173.6200 66.9127 standard deviation of source and background signal pixel dsig dback [mV/s] [mV/s] 1 1.5288 0.3277 2 0.8042 1.4558 3 1.5993 0.4353 4 0.8570 0.8651 S/N ratios for on- and off-position and source and source-to-background contrast pixel S/N_on S/N_off S/N_sour source/back contrast 1 76.55 285.80 14.95 0.2497 2 122.72 54.62 11.53 0.2412 3 54.96 168.04 8.90 0.2016 4 194.92 75.96 83.21 1.5420 Typical source signals of the commissioning cases are in the order of 100 to 200 mV/s, while the uncertainties are in the order of 0.3 to 2 mV/s. >From these three examples it can be seen that the general data quality of these measurements is extremely good: A S/N of 50 corresponds to an uncertainty of the signal of 2%, a S/N of 200 corresponds to 0.5%. It can also be seen that the measurement on rev. 253 had better quality as the same one on rev. 583. The resulting source-to-background contrast tells us that except for the case 3, where 3C 279 was centered on pixel 4, the background is a factor of 2.5 to 5 brighter than the source - which makes polarisation measurements quite a challenge. Comparing case 2 with case 3, one can see the enormous gain of a factor of 4 in S/N of the source only when centering on one array pixel. From these examples we conclude that background subtraction is the crucial limitation in achieving the final polarisation accuracy. 8 Resulting polarisation degrees and angles of polarised and unpolarised control sources In the following we discuss the polarisation results and check for dependence of the error on the source-to-background contrast and limits for accurate polarisation measurements. The following observations were analysed: Log of observations: no. rev. target comment --------------------------------------------------------------- 1 253 3C 279 on 3C 279 centred on array 2 583 3C 279 on 3C 279 centred on array 3 583 3C 279 pix3 3C 279 centred on pixel 4 4 440 HR 5340 HR 5340 centred on array 5 587 HR 5340 on HR 5340 centred on array 6 587 HR 5340 pix3 HR 5340 centred on pixel 4 --------------------------------------------------------------- We discuss the results of each individual measurement: 1) 3C 279, rev. 253, centering on array: average values pixel 1 POL DEG: 27.18 +- 4.07 [%] POL ANG: 60.24 +- 4.90 [deg] +- 15.04 [%] +- 17.24 [deg] pixel 2 POL DEG: 21.14 +- 5.95 [%] POL ANG: 64.83 +- 8.35 [deg] +- 23.62 [%] +- 33.27 [deg] pixel 3 POL DEG: 24.02 +- 3.19 [%] POL ANG: 50.42 +- 4.96 [deg] +- 9.94 [%] +- 14.12 [deg] pixel 4 POL DEG: 20.29 +- 3.17 [%] POL ANG: 49.35 +- 6.33 [deg] +- 9.71 [%] +- 16.77 [deg] debiased polarisation degrees pixel 1 DEBIASED POL DEG: 26.87 [%] pixel 2 DEBIASED POL DEG: 20.28 [%] pixel 3 DEBIASED POL DEG: 23.81 [%] pixel 4 DEBIASED POL DEG: 20.04 [%] S/N ratios for on- and off-position and source and source-to-background contrast pixel S/N_on S/N_off S/N_sour source/back contrast 1 219.48 231.26 25.24 0.1735 2 133.01 84.98 17.08 0.2579 3 206.03 154.60 30.12 0.2690 4 220.14 183.53 30.16 0.2359 The S/N of the measurement is around 30, the source flux is only 1/4 of the background flux. A quite consistent high linear polarisation (> 20%) is derived on a 3.5 to 8 sigma level. Also the polarisation angles are quite consistent. It should be noted that the orientation on the sky is found to be parallel to the milli-arcsecond radio jet which is an additional confirmation of the result. 2) 3C 279, rev. 583, centering on array average values pixel 1 POL DEG: 10.06 +- 8.29 [%] POL ANG: 81.38 +- 22.79 [deg] +- 21.54 [%] +- 54.23 [deg] pixel 2 POL DEG: 10.42 +- 8.79 [%] POL ANG: 76.17 +- 22.72 [deg] +- 31.24 [%] +- 75.03 [deg] pixel 3 POL DEG: 4.50 +- 4.99 [%] POL ANG: 79.46 +- 28.14 [deg] +- 14.07 [%] +- 82.64 [deg] pixel 4 POL DEG: 3.17 +- 4.76 [%] POL ANG: 41.06 +- 56.30 [deg] +- 12.28 [%] +- 157.06 [deg] debiased polarisation degrees pixel 1 DEBIASED POL DEG: 5.69 [%] pixel 2 DEBIASED POL DEG: 5.60 [%] pixel 3 DEBIASED POL DEG: 0.00 [%] pixel 4 DEBIASED POL DEG: 0.00 [%] S/N ratios for on- and off-position and source and source-to-background contrast pixel S/N_on S/N_off S/N_sour source/back contrast 1 49.96 285.80 11.45 0.3008 2 44.00 54.62 11.29 0.4184 3 84.22 168.04 21.55 0.3744 4 90.52 75.96 19.26 0.3896 The S/N in this measurement is between 10 and 20 only (note that photometry shows that the source has become fainter in flux) w.r.t. rev. 253, though the source-to-background ratio is found to be higher than for rev. 253. The polarisation degrees are only on the 1 sigma error level, giving for 2 pixels 0% for the debiased polarisation degree. As can be seen from the next example, the source polarisation has decreased to ~6% on rev. 583. Therefore, 5% polarisation for a 1/3 source-to-background contrast cannot be reliably measured. 3) 3C 279, rev. 583, centering on pixel 4 average values pixel 1 POL DEG: 16.22 +- 6.80 [%] POL ANG: -85.50 +- 10.93 [deg] +- 17.93 [%] +- 26.60 [deg] pixel 2 POL DEG: 6.91 +- 10.28 [%] POL ANG: 2.75 +- 32.78 [deg] +- 29.28 [%] +- 77.64 [deg] pixel 3 POL DEG: 4.97 +- 11.31 [%] POL ANG: -79.02 +- 60.36 [deg] +- 31.19 [%] +- 167.28 [deg] pixel 4 POL DEG: 6.63 +- 1.52 [%] POL ANG: 75.20 +- 5.61 [deg] +- 5.50 [%] +- 20.79 [deg] debiased polarisation degrees pixel 1 DEBIASED POL DEG: 14.73 [%] pixel 2 DEBIASED POL DEG: 0.00 [%] pixel 3 DEBIASED POL DEG: 0.00 [%] pixel 4 DEBIASED POL DEG: 6.45 [%] S/N ratios for on- and off-position and source and source-to-background contrast pixel S/N_on S/N_off S/N_sour source/back contrast 1 76.55 285.80 14.95 0.2497 2 122.72 54.62 11.53 0.2412 3 54.96 168.04 8.90 0.2016 4 194.92 75.96 83.21 1.5420 It can be seen that the pixel 4 measurement has a very high S/N for the source only (> 80) and very reliable polarisation can be measured with 4 sigma. The source flux in the remaining pixels is so small that the S/N is < 15 and no meaningful polarisation results can be obtained. The very high debiased polarisation degree for pixel 1 is not true, if the 2 individual measurements are checked for consistency: they give 23.7% and 9.6%, respectively. Therefore, for fainter sources the source S/N ratio and the consistency of the individual polariser cycles have to be checked beside the derived error for the reliability of the result. 4) HR 5340, rev. 440, centering on array average values pixel 1 POL DEG: 6.15 +- 3.15 [%] POL ANG: 2.25 +- 12.21 [deg] +- 8.96 [%] +- 33.54 [deg] pixel 2 POL DEG: 6.67 +- 4.51 [%] POL ANG: -51.93 +- 21.07 [deg] +- 11.45 [%] +- 61.80 [deg] pixel 3 POL DEG: 10.49 +- 1.97 [%] POL ANG: 29.55 +- 6.00 [deg] +- 7.03 [%] +- 19.88 [deg] pixel 4 POL DEG: 12.04 +- 3.12 [%] POL ANG: -4.05 +- 5.58 [deg] +- 8.29 [%] +- 15.45 [deg] debiased polarisation degrees pixel 1 DEBIASED POL DEG: 5.29 [%] pixel 2 DEBIASED POL DEG: 4.91 [%] pixel 3 DEBIASED POL DEG: 10.30 [%] pixel 4 DEBIASED POL DEG: 11.63 [%] S/N ratios for on- and off-position and source and source-to-background contrast pixel S/N_on S/N_off S/N_sour source/back contrast 1 172.71 228.54 37.03 0.3275 2 68.99 196.36 20.34 0.4357 3 231.76 211.90 57.64 0.4522 4 188.16 294.32 40.26 0.3123 The source is of similar brightness as 3C 279, with a somewhat better source/background contrast. It is expected to be unpolarised, but the debiased polarisation degree gives still a residual positive polarisation value and only within the maximum error the result is consistent with a zero polarisation. The measurement is of similar quality a no. 2 on 3C 279 and we conclude that for the achieved source/background contrast polarisation cannot be derived more accurately, as the 2 sigma errors are in the order of 7%. The error for pixel 3 seems to be accidentially underestimated by the applied method; however in order to be meaningful it should be consistent with the other three pixels, as the point source Airy disk is centred on the array. 5) HR 5340, rev. 587, centering on array average values pixel 1 POL DEG: 11.93 +- 12.90 [%] POL ANG: 58.28 +- 31.85 [deg] +- 35.36 [%] +- 90.79 [deg] pixel 2 POL DEG: 10.73 +- 5.68 [%] POL ANG: 56.80 +- 19.46 [deg] +- 18.83 [%] +- 60.94 [deg] pixel 3 POL DEG: 18.75 +- 3.93 [%] POL ANG: 38.21 +- 8.08 [deg] +- 12.45 [%] +- 20.42 [deg] pixel 4 POL DEG: 2.66 +- 6.95 [%] POL ANG: 71.69 +- 68.63 [deg] +- 22.94 [%] +- 231.18 [deg] debiased polarisation degrees pixel 1 DEBIASED POL DEG: 0.00 [%] pixel 2 DEBIASED POL DEG: 9.10 [%] pixel 3 DEBIASED POL DEG: 18.33 [%] pixel 4 DEBIASED POL DEG: 0.00 [%] S/N ratios for on- and off-position and source and source-to-background contrast pixel S/N_on S/N_off S/N_sour source/back contrast 1 33.00 122.47 7.14 0.2840 2 125.88 72.86 17.46 0.2998 3 135.67 167.54 25.83 0.2900 4 89.02 56.45 16.38 0.3864 As for 3C 279 on rev. 583 the results are much poorer than for HR 5340 on rev. 440 and 3C 279 on rev. 253, source S/N ratios are <25. For two pixels a null result is obtained while the results for the other two pixels show a big scatter for the individual cycles. For this measurement the 1 sigma error level is around 7% and polarisation cannot be determined more accurately. 6) HR 5340, rev. 587, centering on pixel 4 average values pixel 1 POL DEG: 16.19 +- 12.06 [%] POL ANG: 61.39 +- 23.28 [deg] +- 40.78 [%] +- 76.15 [deg] pixel 2 POL DEG: 117.04 +- 71.50 [%] POL ANG: 24.52 +- 18.23 [deg] +- 295.64 [%] +- 73.87 [deg] pixel 3 POL DEG: 113.25 +- 50.72 [%] POL ANG: 31.21 +- 14.32 [deg] +- 203.43 [%] +- 50.82 [deg] pixel 4 POL DEG: 2.84 +- 1.68 [%] POL ANG: 80.37 +- 13.57 [deg] +- 5.65 [%] +- 46.55 [deg] debiased polarisation degrees pixel 1 DEBIASED POL DEG: 10.80 [%] pixel 2 DEBIASED POL DEG: 92.66 [%] pixel 3 DEBIASED POL DEG: 101.25 [%] pixel 4 DEBIASED POL DEG: 2.29 [%] S/N ratios for on- and off-position and source and source-to-background contrast pixel S/N_on S/N_off S/N_sour source/back contrast 1 78.07 122.47 8.32 0.1391 2 112.23 72.86 1.70 0.0280 3 95.25 167.54 2.30 0.0283 4 166.83 56.45 74.78 1.8358 As the corresponding measurement on 3C 279 the measurement on pixel 4 is of high quality, with a source S/N > 70, a source-to-background contrast of 1.8 and a 1 sigma error of 1.7%. The polarisation degree is consistent with 0% within 1.7 sigma (note that for the debiased polarisation degree we use in accordance with Wardle and Kronberg 1974 only the 1 sigma value). The other pixels which have only a weak illumination by the source show very high polarisation uncertainties, demonstrating how sensitive the results become for faint sources on the exact background subtraction. In conclusion we could show the following: Centering the source on one C200 pixels improves the source-to-background contrast and the resulting source S/N and hence the polarisation accuracy significantly (by a factor of about 4). For sources in the flux range 2 to 3 Jy which are covered by our commissioning cases we derive the following limits for the polarisation accuracy: source/background resulting 1 sigma contrast source S/N polarisation error -------------------------------------------------------- 1.5 - 2 70 - 80 1.5 - 1.7 % 0.4 10 - 40 5 - 9 % 0.15 - 0.25 8 - 10 10 - 12 % 0.025 2 50 - 70 % -------------------------------------------------------- The measurements with a source-to-background contrast of 2 proved to give very consistent results both for 5% polarised sources and unpolarised sources. In case of a 20% polarised source, as was 3C 279 on rev. 253, source-to-background contrasts of 0.4 give still reliable results. It should be noted that 3C 279 could not be used to verify the reproducibility of polarisation results, as it is a highly variable source which changed its properties drastically within 11 months. In the same time period the total flux decreased by 23%, too. Appendix A: Polarisation results data sheets for polarised and unpolarised sources obtained with POLCALC_2 file = 3C279SKY_253_160.POL polarisation calculation done for detector C200 derivation of SKY POLARISATION source name: 3C 279 signal file used: 3C279SKY_253_160.DAT number of polariser cycles: 2 INPUT SIGNALS: polariser cycle no. 1: pixel pol. orientation source signal background signal [deg] [mV/s] [mV/s] 1 0 198.7650 172.4360 1 120 207.8110 179.2910 1 240 205.6870 170.2470 2 0 161.2230 129.0320 2 120 164.9780 133.0260 2 240 179.7840 137.7410 3 0 171.6260 137.1250 3 120 168.5010 137.2780 3 240 170.4970 128.9220 4 0 142.4230 115.3280 4 120 141.2540 116.9220 4 240 148.7580 116.8370 polariser cycle no. 2: pixel pol. orientation source signal background signal [deg] [mV/s] [mV/s] 1 0 197.6480 172.0950 1 120 208.9680 181.6230 1 240 208.1560 169.8950 2 0 159.0890 133.7910 2 120 168.0170 133.7680 2 240 181.3230 139.0890 3 0 170.4490 135.0400 3 120 170.1010 138.0510 3 240 168.8050 127.3210 4 0 141.9310 116.8980 4 120 141.3240 116.9800 4 240 150.7720 118.0960 average signals of all polariser cycles: pixel pol. orientation source signal background signal [deg] [mV/s] [mV/s] 1 0 198.2065 172.2655 1 120 208.3895 180.4570 1 240 206.9215 170.0710 2 0 160.1560 131.4115 2 120 166.4975 133.3970 2 240 180.5535 138.4150 3 0 171.0375 136.0825 3 120 169.3010 137.6645 3 240 169.6510 128.1215 4 0 142.1770 116.1130 4 120 141.2890 116.9510 4 240 149.7650 117.4665 standard deviation of source and background signal pixel dsig dback [mV/s] [mV/s] 1 0.9318 0.7536 2 1.2711 1.5816 3 0.8251 0.8665 4 0.6560 0.6367 S/N ratios for on- and off-position and source and source-to-background contrast pixel S/N_on S/N_off S/N_sour source/back contrast 1 219.48 231.26 25.24 0.1735 2 133.01 84.98 17.08 0.2579 3 206.03 154.60 30.12 0.2690 4 220.14 183.53 30.16 0.2359 POLARISATION DEGREE AND ANGLE: first error = Gaussian error second error = maximum error polariser cycle no. 1 pixel 1 POL DEG: 22.63 +- 4.09 [%] POL ANG: 60.85 +- 5.86 [deg] +- 13.43 [%] +- 17.42 [deg] pixel 2 POL DEG: 18.42 +- 5.41 [%] POL ANG: 52.20 +- 9.93 [deg] +- 16.68 [%] +- 27.22 [deg] pixel 3 POL DEG: 25.08 +- 3.21 [%] POL ANG: 50.87 +- 4.78 [deg] +- 9.71 [%] +- 10.95 [deg] pixel 4 POL DEG: 19.05 +- 3.09 [%] POL ANG: 44.64 +- 6.72 [deg] +- 8.06 [%] +- 12.21 [deg] polariser cycle no. 2 pixel 1 POL DEG: 31.69 +- 4.06 [%] POL ANG: 59.80 +- 4.22 [deg] +- 13.92 [%] +- 12.92 [deg] pixel 2 POL DEG: 27.08 +- 6.47 [%] POL ANG: 73.63 +- 6.29 [deg] +- 21.54 [%] +- 21.81 [deg] pixel 3 POL DEG: 22.99 +- 3.17 [%] POL ANG: 49.94 +- 5.15 [deg] +- 9.34 [%] +- 11.21 [deg] pixel 4 POL DEG: 22.03 +- 3.31 [%] POL ANG: 53.48 +- 5.79 [deg] +- 10.52 [%] +- 13.77 [deg] average values pixel 1 POL DEG: 27.18 +- 4.07 [%] POL ANG: 60.24 +- 4.90 [deg] +- 15.04 [%] +- 17.24 [deg] pixel 2 POL DEG: 21.14 +- 5.95 [%] POL ANG: 64.83 +- 8.35 [deg] +- 23.62 [%] +- 33.27 [deg] pixel 3 POL DEG: 24.02 +- 3.19 [%] POL ANG: 50.42 +- 4.96 [deg] +- 9.94 [%] +- 14.12 [deg] pixel 4 POL DEG: 20.29 +- 3.17 [%] POL ANG: 49.35 +- 6.33 [deg] +- 9.71 [%] +- 16.77 [deg] debiased polarisation degrees pixel 1 DEBIASED POL DEG: 26.87 [%] pixel 2 DEBIASED POL DEG: 20.28 [%] pixel 3 DEBIASED POL DEG: 23.81 [%] pixel 4 DEBIASED POL DEG: 20.04 [%] file = 3C279SKY_583_160.POL polarisation calculation done for detector C200 derivation of SKY POLARISATION source name: 3C 279 signal file used: 3C279SKY_583_160.DAT number of polariser cycles: 2 INPUT SIGNALS: polariser cycle no. 1: pixel pol. orientation source signal background signal [deg] [mV/s] [mV/s] 1 0 115.1570 92.5406 1 120 124.4350 97.8266 1 240 120.3430 91.2814 2 0 101.2510 74.9207 2 120 112.9760 79.0803 2 240 117.7050 80.6280 3 0 100.0710 74.2678 3 120 102.2010 74.4030 3 240 97.3969 70.2750 4 0 87.4132 62.2936 4 120 91.4236 66.2594 4 240 92.4521 66.2418 polariser cycle no. 2: pixel pol. orientation source signal background signal [deg] [mV/s] [mV/s] 1 0 120.2830 92.4645 1 120 130.1930 96.8529 1 240 120.4850 90.9352 2 0 108.1900 76.7913 2 120 116.2250 81.9175 2 240 120.3480 83.7336 3 0 102.0370 74.5604 3 120 105.2260 75.6450 3 240 96.2854 69.7583 4 0 88.9319 64.0274 4 120 93.8790 67.8958 4 240 93.8091 67.5836 average signals of all polariser cycles: pixel pol. orientation source signal background signal [deg] [mV/s] [mV/s] 1 0 117.7200 92.5026 1 120 127.3140 97.3398 1 240 120.4140 91.1083 2 0 104.7205 75.8560 2 120 114.6005 80.4989 2 240 119.0265 82.1808 3 0 101.0540 74.4141 3 120 103.7135 75.0240 3 240 96.8411 70.0167 4 0 88.1726 63.1605 4 120 92.6513 67.0776 4 240 93.1306 66.9127 standard deviation of source and background signal pixel dsig dback [mV/s] [mV/s] 1 2.4382 0.3277 2 2.5630 1.4558 3 1.1938 0.4353 4 1.0088 0.8651 S/N ratios for on- and off-position and source and source-to-background contrast pixel S/N_on S/N_off S/N_sour source/back contrast 1 49.96 285.80 11.45 0.3008 2 44.00 54.62 11.29 0.4184 3 84.22 168.04 21.55 0.3744 4 90.52 75.96 19.26 0.3896 POLARISATION DEGREE AND ANGLE: first error = Gaussian error second error = maximum error polariser cycle no. 1 pixel 1 POL DEG: 16.57 +- 8.84 [%] POL ANG: 70.26 +- 15.15 [deg] +- 24.33 [%] +- 41.38 [deg] pixel 2 POL DEG: 16.50 +- 9.14 [%] POL ANG: 79.64 +- 14.59 [deg] +- 27.76 [%] +- 42.70 [deg] pixel 3 POL DEG: 7.21 +- 4.89 [%] POL ANG: 71.33 +- 18.56 [deg] +- 13.49 [%] +- 53.09 [deg] pixel 4 POL DEG: 4.37 +- 4.91 [%] POL ANG: 36.06 +- 40.34 [deg] +- 13.63 [%] +- 98.46 [deg] polariser cycle no. 2 pixel 1 POL DEG: 7.72 +- 7.68 [%] POL ANG: -76.38 +- 27.89 [deg] +- 20.13 [%] +- 72.80 [deg] pixel 2 POL DEG: 5.13 +- 8.24 [%] POL ANG: 65.34 +- 46.80 [deg] +- 25.73 [%] +- 146.07 [deg] pixel 3 POL DEG: 2.90 +- 4.90 [%] POL ANG: -79.45 +- 43.11 [deg] +- 12.35 [%] +- 123.30 [deg] pixel 4 POL DEG: 2.18 +- 4.79 [%] POL ANG: 51.16 +- 81.02 [deg] +- 12.46 [%] +- 188.45 [deg] average values pixel 1 POL DEG: 10.06 +- 8.29 [%] POL ANG: 81.38 +- 22.79 [deg] +- 21.54 [%] +- 54.23 [deg] pixel 2 POL DEG: 10.42 +- 8.79 [%] POL ANG: 76.17 +- 22.72 [deg] +- 31.24 [%] +- 75.03 [deg] pixel 3 POL DEG: 4.50 +- 4.99 [%] POL ANG: 79.46 +- 28.14 [deg] +- 14.07 [%] +- 82.64 [deg] pixel 4 POL DEG: 3.17 +- 4.76 [%] POL ANG: 41.06 +- 56.30 [deg] +- 12.28 [%] +- 157.06 [deg] debiased polarisation degrees pixel 1 DEBIASED POL DEG: 5.69 [%] pixel 2 DEBIASED POL DEG: 5.60 [%] pixel 3 DEBIASED POL DEG: 0.00 [%] pixel 4 DEBIASED POL DEG: 0.00 [%] file = 3C279PIX3SKY_583_160.POL polarisation calculation done for detector C200 derivation of SKY POLARISATION source name: 3C 279 signal file used: 3C279PIX3SKY_583_160.DAT number of polariser cycles: 2 INPUT SIGNALS: polariser cycle no. 1: pixel pol. orientation source signal background signal [deg] [mV/s] [mV/s] 1 0 109.6720 92.5406 1 120 123.7910 97.8266 1 240 115.0120 91.2814 2 0 95.2893 74.9207 2 120 98.9232 79.0803 2 240 100.2170 80.6280 3 0 90.9769 74.2678 3 120 90.9414 74.4030 3 240 82.9811 70.2750 4 0 156.7940 62.2936 4 120 170.5130 66.2594 4 240 172.3980 66.2418 polariser cycle no. 2: pixel pol. orientation source signal background signal [deg] [mV/s] [mV/s] 1 0 114.4980 92.4645 1 120 124.0150 96.8529 1 240 115.1940 90.9352 2 0 95.2561 76.7913 2 120 99.8498 81.9175 2 240 102.5850 83.7336 3 0 86.4319 74.5604 3 120 90.8595 75.6450 3 240 85.1978 69.7583 4 0 156.2200 64.0274 4 120 171.5340 67.8958 4 240 174.8420 67.5836 average signals of all polariser cycles: pixel pol. orientation source signal background signal [deg] [mV/s] [mV/s] 1 0 112.0850 92.5026 1 120 123.9030 97.3398 1 240 115.1030 91.1083 2 0 95.2727 75.8560 2 120 99.3865 80.4989 2 240 101.4010 82.1808 3 0 88.7044 74.4141 3 120 90.9005 75.0240 3 240 84.0895 70.0167 4 0 156.5070 63.1605 4 120 171.0235 67.0776 4 240 173.6200 66.9127 standard deviation of source and background signal pixel dsig dback [mV/s] [mV/s] 1 1.5288 0.3277 2 0.8042 1.4558 3 1.5993 0.4353 4 0.8570 0.8651 S/N ratios for on- and off-position and source and source-to-background contrast pixel S/N_on S/N_off S/N_sour source/back contrast 1 76.55 285.80 14.95 0.2497 2 122.72 54.62 11.53 0.2412 3 54.96 168.04 8.90 0.2016 4 194.92 75.96 83.21 1.5420 POLARISATION DEGREE AND ANGLE: first error = Gaussian error second error = maximum error polariser cycle no. 1 pixel 1 POL DEG: 23.71 +- 7.22 [%] POL ANG: -87.68 +- 7.83 [deg] +- 17.27 [%] +- 17.58 [deg] pixel 2 POL DEG: 8.01 +- 9.85 [%] POL ANG: -4.55 +- 27.38 [deg] +- 21.05 [%] +- 65.17 [deg] pixel 3 POL DEG: 13.45 +- 10.47 [%] POL ANG: -24.23 +- 22.59 [deg] +- 31.00 [%] +- 66.21 [deg] pixel 4 POL DEG: 5.53 +- 1.52 [%] POL ANG: 75.22 +- 6.69 [deg] +- 4.64 [%] +- 22.27 [deg] polariser cycle no. 2 pixel 1 POL DEG: 9.61 +- 6.40 [%] POL ANG: -80.60 +- 17.74 [deg] +- 16.42 [%] +- 47.00 [deg] pixel 2 POL DEG: 6.40 +- 10.31 [%] POL ANG: 12.74 +- 39.13 [deg] +- 25.84 [%] +- 108.74 [deg] pixel 3 POL DEG: 20.47 +- 11.85 [%] POL ANG: 80.00 +- 15.20 [deg] +- 30.59 [%] +- 39.53 [deg] pixel 4 POL DEG: 7.74 +- 1.53 [%] POL ANG: 75.19 +- 4.83 [deg] +- 4.76 [%] +- 16.33 [deg] average values pixel 1 POL DEG: 16.22 +- 6.80 [%] POL ANG: -85.50 +- 10.93 [deg] +- 17.93 [%] +- 26.60 [deg] pixel 2 POL DEG: 6.91 +- 10.28 [%] POL ANG: 2.75 +- 32.78 [deg] +- 29.28 [%] +- 77.64 [deg] pixel 3 POL DEG: 4.97 +- 11.31 [%] POL ANG: -79.02 +- 60.36 [deg] +- 31.19 [%] +- 167.28 [deg] pixel 4 POL DEG: 6.63 +- 1.52 [%] POL ANG: 75.20 +- 5.61 [deg] +- 5.50 [%] +- 20.79 [deg] debiased polarisation degrees pixel 1 DEBIASED POL DEG: 14.73 [%] pixel 2 DEBIASED POL DEG: 0.00 [%] pixel 3 DEBIASED POL DEG: 0.00 [%] pixel 4 DEBIASED POL DEG: 6.45 [%] file = hr5340sky_440_160.pol polarisation calculation done for detector C200 derivation of SKY POLARISATION source name: HR 5340 signal file used: hr5340sky_440_160.dat number of polariser cycles: 2 INPUT SIGNALS: polariser cycle no. 1: pixel pol. orientation source signal background signal [deg] [mV/s] [mV/s] 1 0 201.7750 150.0360 1 120 220.4050 167.9620 1 240 204.6020 154.7860 2 0 167.4900 117.0920 2 120 187.4760 129.3950 2 240 182.4830 131.7820 3 0 166.5210 112.5000 3 120 170.3150 120.9870 3 240 160.0440 107.8430 4 0 144.4450 106.5170 4 120 147.9100 114.9080 4 240 143.0470 111.6520 polariser cycle no. 2: pixel pol. orientation source signal background signal [deg] [mV/s] [mV/s] 1 0 204.5580 149.4360 1 120 217.9540 166.0250 1 240 203.6710 155.5770 2 0 167.8490 115.4120 2 120 189.9930 129.5840 2 240 190.3770 132.9050 3 0 165.7210 110.9060 3 120 169.4660 121.4670 3 240 158.1180 108.1670 4 0 144.5220 107.5160 4 120 149.8310 114.5170 4 240 144.5640 111.1300 average signals of all polariser cycles: pixel pol. orientation source signal background signal [deg] [mV/s] [mV/s] 1 0 203.1665 149.7360 1 120 219.1795 166.9935 1 240 204.1365 155.1815 2 0 167.6695 116.2520 2 120 188.7345 129.4895 2 240 186.4300 132.3435 3 0 166.1210 111.7030 3 120 169.8905 121.2270 3 240 159.0810 108.0050 4 0 144.4835 107.0165 4 120 148.8705 114.7125 4 240 143.8055 111.3910 standard deviation of source and background signal pixel dsig dback [mV/s] [mV/s] 1 1.2091 0.6883 2 2.6226 0.6418 3 0.7121 0.5363 4 0.7744 0.3773 S/N ratios for on- and off-position and source and source-to-background contrast pixel S/N_on S/N_off S/N_sour source/back contrast 1 172.71 228.54 37.03 0.3275 2 68.99 196.36 20.34 0.4357 3 231.76 211.90 57.64 0.4522 4 188.16 294.32 40.26 0.3123 POLARISATION DEGREE AND ANGLE: first error = Gaussian error second error = maximum error polariser cycle no. 1 pixel 1 POL DEG: 3.15 +- 3.10 [%] POL ANG: 11.43 +- 24.86 [deg] +- 9.06 [%] +- 80.51 [deg] pixel 2 POL DEG: 9.37 +- 4.65 [%] POL ANG: -45.29 +- 15.50 [deg] +- 9.34 [%] +- 35.53 [deg] pixel 3 POL DEG: 10.16 +- 1.87 [%] POL ANG: 34.98 +- 6.31 [deg] +- 5.99 [%] +- 16.03 [deg] pixel 4 POL DEG: 15.51 +- 3.19 [%] POL ANG: -2.76 +- 4.38 [deg] +- 7.12 [%] +- 11.36 [deg] polariser cycle no. 2 pixel 1 POL DEG: 9.35 +- 3.13 [%] POL ANG: -0.77 +- 7.95 [deg] +- 7.18 [%] +- 20.42 [deg] pixel 2 POL DEG: 4.82 +- 4.52 [%] POL ANG: -64.28 +- 27.50 [deg] +- 13.45 [%] +- 82.86 [deg] pixel 3 POL DEG: 11.18 +- 2.08 [%] POL ANG: 24.54 +- 5.49 [deg] +- 6.71 [%] +- 17.12 [deg] pixel 4 POL DEG: 8.73 +- 3.05 [%] POL ANG: -6.26 +- 7.66 [deg] +- 7.24 [%] +- 21.79 [deg] average values pixel 1 POL DEG: 6.15 +- 3.15 [%] POL ANG: 2.25 +- 12.21 [deg] +- 8.96 [%] +- 33.54 [deg] pixel 2 POL DEG: 6.67 +- 4.51 [%] POL ANG: -51.93 +- 21.07 [deg] +- 11.45 [%] +- 61.80 [deg] pixel 3 POL DEG: 10.49 +- 1.97 [%] POL ANG: 29.55 +- 6.00 [deg] +- 7.03 [%] +- 19.88 [deg] pixel 4 POL DEG: 12.04 +- 3.12 [%] POL ANG: -4.05 +- 5.58 [deg] +- 8.29 [%] +- 15.45 [deg] debiased polarisation degrees pixel 1 DEBIASED POL DEG: 5.29 [%] pixel 2 DEBIASED POL DEG: 4.91 [%] pixel 3 DEBIASED POL DEG: 10.30 [%] pixel 4 DEBIASED POL DEG: 11.63 [%] file = hr5340sky_587_160.pol polarisation calculation done for detector C200 derivation of SKY POLARISATION source name: HR 5340 signal file used: hr5340sky_587_160.dat number of polariser cycles: 2 INPUT SIGNALS: polariser cycle no. 1: pixel pol. orientation source signal background signal [deg] [mV/s] [mV/s] 1 0 96.5096 76.2923 1 120 99.6163 81.9219 1 240 93.6226 73.0611 2 0 78.4217 61.6722 2 120 84.4508 66.2709 2 240 85.4118 63.1625 3 0 79.4471 61.8904 3 120 81.4942 65.4024 3 240 74.2467 55.7449 4 0 71.9113 52.0929 4 120 77.0900 55.6276 4 240 73.7187 52.0331 polariser cycle no. 2: pixel pol. orientation source signal background signal [deg] [mV/s] [mV/s] 1 0 95.0937 74.6230 1 120 107.5050 82.2792 1 240 98.6060 72.0568 2 0 79.1729 60.8583 2 120 85.9428 67.0658 2 240 86.6742 65.7023 3 0 80.2487 60.7775 3 120 80.0458 65.1266 3 240 75.0216 55.7878 4 0 73.5193 53.4590 4 120 78.3039 57.0129 4 240 75.4619 54.3562 average signals of all polariser cycles: pixel pol. orientation source signal background signal [deg] [mV/s] [mV/s] 1 0 95.8017 75.4576 1 120 103.5607 82.1005 1 240 96.1143 72.5590 2 0 78.7973 61.2653 2 120 85.1968 66.6684 2 240 86.0430 64.4324 3 0 79.8479 61.3340 3 120 80.7700 65.2645 3 240 74.6341 55.7663 4 0 72.7153 52.7760 4 120 77.6970 56.3203 4 240 74.5903 53.1947 standard deviation of source and background signal pixel dsig dback [mV/s] [mV/s] 1 2.9845 0.6263 2 0.6621 0.8801 3 0.5780 0.3628 4 0.8425 0.9582 S/N ratios for on- and off-position and source and source-to-background contrast pixel S/N_on S/N_off S/N_sour source/back contrast 1 33.00 122.47 7.14 0.2840 2 125.88 72.86 17.46 0.2998 3 135.67 167.54 25.83 0.2900 4 89.02 56.45 16.38 0.3864 POLARISATION DEGREE AND ANGLE: first error = Gaussian error second error = maximum error polariser cycle no. 1 pixel 1 POL DEG: 15.24 +- 14.39 [%] POL ANG: 33.08 +- 27.88 [deg] +- 37.01 [%] +- 70.64 [deg] pixel 2 POL DEG: 15.47 +- 6.02 [%] POL ANG: 60.55 +- 13.19 [deg] +- 18.36 [%] +- 35.60 [deg] pixel 3 POL DEG: 14.88 +- 3.91 [%] POL ANG: 45.13 +- 10.46 [deg] +- 10.22 [%] +- 17.31 [deg] pixel 4 POL DEG: 3.89 +- 6.99 [%] POL ANG: 72.70 +- 46.21 [deg] +- 18.95 [%] +- 135.50 [deg] polariser cycle no. 2 pixel 1 POL DEG: 16.70 +- 12.04 [%] POL ANG: 75.63 +- 20.09 [deg] +- 33.61 [%] +- 54.82 [deg] pixel 2 POL DEG: 6.52 +- 5.21 [%] POL ANG: 47.95 +- 33.20 [deg] +- 12.90 [%] +- 68.69 [deg] pixel 3 POL DEG: 23.19 +- 4.01 [%] POL ANG: 33.91 +- 6.30 [deg] +- 12.70 [%] +- 15.17 [deg] pixel 4 POL DEG: 1.43 +- 6.79 [%] POL ANG: 68.92 +- 132.44 [deg] +- 18.98 [%] +- 378.18 [deg] average values pixel 1 POL DEG: 11.93 +- 12.90 [%] POL ANG: 58.28 +- 31.85 [deg] +- 35.36 [%] +- 90.79 [deg] pixel 2 POL DEG: 10.73 +- 5.68 [%] POL ANG: 56.80 +- 19.46 [deg] +- 18.83 [%] +- 60.94 [deg] pixel 3 POL DEG: 18.75 +- 3.93 [%] POL ANG: 38.21 +- 8.08 [deg] +- 12.45 [%] +- 20.42 [deg] pixel 4 POL DEG: 2.66 +- 6.95 [%] POL ANG: 71.69 +- 68.63 [deg] +- 22.94 [%] +- 231.18 [deg] debiased polarisation degrees pixel 1 DEBIASED POL DEG: 0.00 [%] pixel 2 DEBIASED POL DEG: 9.10 [%] pixel 3 DEBIASED POL DEG: 18.33 [%] pixel 4 DEBIASED POL DEG: 0.00 [%] file = hr5340pix3sky_587_160.pol polarisation calculation done for detector C200 derivation of SKY POLARISATION source name: HR 5340 signal file used: hr5340pix3sky_587_160.dat number of polariser cycles: 2 INPUT SIGNALS: polariser cycle no. 1: pixel pol. orientation source signal background signal [deg] [mV/s] [mV/s] 1 0 83.8139 76.2923 1 120 93.6744 81.9219 1 240 84.0654 73.0611 2 0 65.0063 61.6722 2 120 66.8582 66.2709 2 240 66.4649 63.1625 3 0 64.9232 61.8904 3 120 65.2348 65.4024 3 240 58.3609 55.7449 4 0 147.4700 52.0929 4 120 159.2310 55.6276 4 240 153.3430 52.0331 polariser cycle no. 2: pixel pol. orientation source signal background signal [deg] [mV/s] [mV/s] 1 0 86.3673 74.6230 1 120 91.3850 82.2792 1 240 84.9389 72.0568 2 0 63.4164 60.8583 2 120 66.4318 67.0658 2 240 67.3250 65.7023 3 0 62.8528 60.7775 3 120 65.3737 65.1266 3 240 58.3213 55.7878 4 0 146.5610 53.4590 4 120 158.0150 57.0129 4 240 155.8230 54.3562 average signals of all polariser cycles: pixel pol. orientation source signal background signal [deg] [mV/s] [mV/s] 1 0 85.0906 75.4576 1 120 92.5297 82.1005 1 240 84.5022 72.5590 2 0 64.2113 61.2653 2 120 66.6450 66.6684 2 240 66.8950 64.4324 3 0 63.8880 61.3340 3 120 65.3043 65.2645 3 240 58.3411 55.7663 4 0 147.0155 52.7760 4 120 158.6230 56.3203 4 240 154.5830 53.1947 standard deviation of source and background signal pixel dsig dback [mV/s] [mV/s] 1 1.1191 0.6263 2 0.5873 0.8801 3 0.6563 0.3628 4 0.9195 0.9582 S/N ratios for on- and off-position and source and source-to-background contrast pixel S/N_on S/N_off S/N_sour source/back contrast 1 78.07 122.47 8.32 0.1391 2 112.23 72.86 1.70 0.0280 3 95.25 167.54 2.30 0.0283 4 166.83 56.45 74.78 1.8358 POLARISATION DEGREE AND ANGLE: first error = Gaussian error second error = maximum error polariser cycle no. 1 pixel 1 POL DEG: 26.28 +- 14.81 [%] POL ANG: -89.74 +- 12.94 [deg] +- 32.77 [%] +- 30.31 [deg] pixel 2 POL DEG: 86.56 +- 49.51 [%] POL ANG: 28.08 +- 18.38 [deg] +- 172.36 [%] +- 56.68 [deg] pixel 3 POL DEG: 126.35 +- 49.73 [%] POL ANG: 27.59 +- 12.11 [deg] +- 194.18 [%] +- 43.12 [deg] pixel 4 POL DEG: 2.25 +- 1.70 [%] POL ANG: 89.26 +- 16.41 [deg] +- 3.85 [%] +- 42.41 [deg] polariser cycle no. 2 pixel 1 POL DEG: 26.97 +- 10.88 [%] POL ANG: 37.52 +- 13.80 [deg] +- 32.59 [%] +- 33.26 [deg] pixel 2 POL DEG: 181.80 +- 123.47 [%] POL ANG: 21.08 +- 18.92 [deg] +- 481.60 [%] +- 75.36 [deg] pixel 3 POL DEG: 101.20 +- 51.93 [%] POL ANG: 36.33 +- 17.10 [deg] +- 187.32 [%] +- 44.73 [deg] pixel 4 POL DEG: 3.62 +- 1.63 [%] POL ANG: 74.81 +- 11.26 [deg] +- 4.95 [%] +- 37.07 [deg] average values pixel 1 POL DEG: 16.19 +- 12.06 [%] POL ANG: 61.39 +- 23.28 [deg] +- 40.78 [%] +- 76.15 [deg] pixel 2 POL DEG: 117.04 +- 71.50 [%] POL ANG: 24.52 +- 18.23 [deg] +- 295.64 [%] +- 73.87 [deg] pixel 3 POL DEG: 113.25 +- 50.72 [%] POL ANG: 31.21 +- 14.32 [deg] +- 203.43 [%] +- 50.82 [deg] pixel 4 POL DEG: 2.84 +- 1.68 [%] POL ANG: 80.37 +- 13.57 [deg] +- 5.65 [%] +- 46.55 [deg] debiased polarisation degrees pixel 1 DEBIASED POL DEG: 10.80 [%] pixel 2 DEBIASED POL DEG: 92.66 [%] pixel 3 DEBIASED POL DEG: 101.25 [%] pixel 4 DEBIASED POL DEG: 2.29 [%] Appendix B: Instrumental polarisation results data sheets from unpolarised sources obtained with POLCALC_2 file = 3c279off_253_160.pol polarisation calculation done for detector C200 derivation of INSTRUMENTAL POLARISATION source name: 3C 279 background signal file used: 3c279off_253_160.dat number of polariser cycles: 2 INPUT SIGNALS: polariser cycle no. 1: pixel pol. orientation source signal background signal [deg] [mV/s] [mV/s] 1 0 172.4360 0.0000 1 120 179.2910 0.0000 1 240 170.2470 0.0000 2 0 129.0320 0.0000 2 120 133.0260 0.0000 2 240 137.7410 0.0000 3 0 137.1250 0.0000 3 120 137.2780 0.0000 3 240 128.9220 0.0000 4 0 115.3280 0.0000 4 120 116.9220 0.0000 4 240 116.8370 0.0000 polariser cycle no. 2: pixel pol. orientation source signal background signal [deg] [mV/s] [mV/s] 1 0 172.0950 0.0000 1 120 181.6230 0.0000 1 240 169.8950 0.0000 2 0 133.7910 0.0000 2 120 133.7680 0.0000 2 240 139.0890 0.0000 3 0 135.0400 0.0000 3 120 138.0510 0.0000 3 240 127.3210 0.0000 4 0 116.8980 0.0000 4 120 116.9800 0.0000 4 240 118.0960 0.0000 average signals of all polariser cycles: pixel pol. orientation source signal background signal [deg] [mV/s] [mV/s] 1 0 172.2655 0.0000 1 120 180.4570 0.0000 1 240 170.0710 0.0000 2 0 131.4115 0.0000 2 120 133.3970 0.0000 2 240 138.4150 0.0000 3 0 136.0825 0.0000 3 120 137.6645 0.0000 3 240 128.1215 0.0000 4 0 116.1130 0.0000 4 120 116.9510 0.0000 4 240 117.4665 0.0000 standard deviation of source and background signal pixel dsig dback [mV/s] [mV/s] 1 0.7536 0.0000 2 1.5816 0.0000 3 0.8665 0.0000 4 0.6367 0.0000 S/N ratios for on- and off-position and source and source-to-background contrast pixel S/N_on S/N_off S/N_sour source/back contrast 1 231.26 0.00 0.00 0.0000 2 84.98 0.00 0.00 0.0000 3 154.60 0.00 0.00 0.0000 4 183.53 0.00 0.00 0.0000 POLARISATION DEGREE AND ANGLE: first error = Gaussian error second error = maximum error polariser cycle no. 1 pixel 1 POL DEG: 3.48 +- 0.41 [%] POL ANG: -53.30 +- 3.26 [deg] +- 0.85 [%] +- 6.96 [deg] pixel 2 POL DEG: 4.20 +- 1.08 [%] POL ANG: 73.64 +- 7.38 [deg] +- 2.49 [%] +- 16.41 [deg] pixel 3 POL DEG: 4.56 +- 0.60 [%] POL ANG: -30.46 +- 3.72 [deg] +- 1.37 [%] +- 8.73 [deg] pixel 4 POL DEG: 0.99 +- 0.50 [%] POL ANG: -88.65 +- 14.38 [deg] +- 0.88 [%] +- 21.54 [deg] polariser cycle no. 2 pixel 1 POL DEG: 4.58 +- 0.41 [%] POL ANG: -54.92 +- 2.49 [deg] +- 0.91 [%] +- 5.63 [deg] pixel 2 POL DEG: 2.90 +- 1.06 [%] POL ANG: 59.90 +- 10.47 [deg] +- 2.29 [%] +- 23.27 [deg] pixel 3 POL DEG: 5.32 +- 0.61 [%] POL ANG: -37.90 +- 3.19 [deg] +- 1.26 [%] +- 6.67 [deg] pixel 4 POL DEG: 0.73 +- 0.49 [%] POL ANG: 61.76 +- 19.28 [deg] +- 1.05 [%] +- 42.31 [deg] average values pixel 1 POL DEG: 4.03 +- 0.41 [%] POL ANG: -54.22 +- 2.82 [deg] +- 0.88 [%] +- 6.22 [deg] pixel 2 POL DEG: 3.45 +- 1.07 [%] POL ANG: 67.99 +- 8.90 [deg] +- 2.46 [%] +- 20.39 [deg] pixel 3 POL DEG: 4.90 +- 0.60 [%] POL ANG: -34.45 +- 3.46 [deg] +- 1.31 [%] +- 7.74 [deg] pixel 4 POL DEG: 0.75 +- 0.49 [%] POL ANG: 78.92 +- 18.89 [deg] +- 1.04 [%] +- 37.14 [deg] debiased polarisation degrees pixel 1 DEBIASED POL DEG: 4.01 [%] pixel 2 DEBIASED POL DEG: 3.27 [%] pixel 3 DEBIASED POL DEG: 4.86 [%] pixel 4 DEBIASED POL DEG: 0.56 [%] file = hr5340off_440_160.pol polarisation calculation done for detector C200 derivation of INSTRUMENTAL POLARISATION source name: HR 5340 background signal file used: hr5340off_440_160.dat number of polariser cycles: 2 INPUT SIGNALS: polariser cycle no. 1: pixel pol. orientation source signal background signal [deg] [mV/s] [mV/s] 1 0 150.6360 0.0000 1 120 169.8990 0.0000 1 240 153.9950 0.0000 2 0 118.7720 0.0000 2 120 129.2060 0.0000 2 240 130.6590 0.0000 3 0 114.0940 0.0000 3 120 120.5070 0.0000 3 240 107.5180 0.0000 4 0 105.5170 0.0000 4 120 115.2980 0.0000 4 240 112.1740 0.0000 polariser cycle no. 2: pixel pol. orientation source signal background signal [deg] [mV/s] [mV/s] 1 0 149.4360 0.0000 1 120 166.0250 0.0000 1 240 155.5770 0.0000 2 0 115.4120 0.0000 2 120 129.5840 0.0000 2 240 132.9050 0.0000 3 0 110.9060 0.0000 3 120 121.4670 0.0000 3 240 108.1670 0.0000 4 0 107.5160 0.0000 4 120 114.5170 0.0000 4 240 111.1300 0.0000 average signals of all polariser cycles: pixel pol. orientation source signal background signal [deg] [mV/s] [mV/s] 1 0 150.0360 0.0000 1 120 167.9620 0.0000 1 240 154.7860 0.0000 2 0 117.0920 0.0000 2 120 129.3950 0.0000 2 240 131.7820 0.0000 3 0 112.5000 0.0000 3 120 120.9870 0.0000 3 240 107.8425 0.0000 4 0 106.5165 0.0000 4 120 114.9075 0.0000 4 240 111.6520 0.0000 standard deviation of source and background signal pixel dsig dback [mV/s] [mV/s] 1 1.3766 0.0000 2 1.2836 0.0000 3 1.0727 0.0000 4 0.7547 0.0000 S/N ratios for on- and off-position and source and source-to-background contrast pixel S/N_on S/N_off S/N_sour source/back contrast 1 114.48 0.00 0.00 0.0000 2 98.23 0.00 0.00 0.0000 3 106.07 0.00 0.00 0.0000 4 147.11 0.00 0.00 0.0000 POLARISATION DEGREE AND ANGLE: first error = Gaussian error second error = maximum error polariser cycle no. 1 pixel 1 POL DEG: 8.35 +- 0.82 [%] POL ANG: -64.70 +- 2.79 [deg] +- 2.03 [%] +- 7.03 [deg] pixel 2 POL DEG: 6.59 +- 0.95 [%] POL ANG: 86.79 +- 4.01 [deg] +- 1.93 [%] +- 6.65 [deg] pixel 3 POL DEG: 7.31 +- 0.89 [%] POL ANG: -44.80 +- 3.35 [deg] +- 1.53 [%] +- 5.52 [deg] pixel 4 POL DEG: 5.77 +- 0.64 [%] POL ANG: -80.90 +- 3.09 [deg] +- 1.46 [%] +- 6.36 [deg] polariser cycle no. 2 pixel 1 POL DEG: 6.85 +- 0.81 [%] POL ANG: -70.74 +- 3.39 [deg] +- 2.01 [%] +- 8.24 [deg] pixel 2 POL DEG: 9.46 +- 0.98 [%] POL ANG: 84.86 +- 2.81 [deg] +- 2.13 [%] +- 5.15 [deg] pixel 3 POL DEG: 7.94 +- 0.89 [%] POL ANG: -54.38 +- 3.12 [deg] +- 1.94 [%] +- 6.94 [deg] pixel 4 POL DEG: 4.04 +- 0.63 [%] POL ANG: -75.54 +- 4.40 [deg] +- 1.47 [%] +- 9.83 [deg] average values pixel 1 POL DEG: 7.56 +- 0.81 [%] POL ANG: -67.41 +- 3.08 [deg] +- 2.03 [%] +- 7.68 [deg] pixel 2 POL DEG: 8.02 +- 0.96 [%] POL ANG: 85.65 +- 3.31 [deg] +- 2.04 [%] +- 5.80 [deg] pixel 3 POL DEG: 7.52 +- 0.89 [%] POL ANG: -49.78 +- 3.27 [deg] +- 1.75 [%] +- 6.42 [deg] pixel 4 POL DEG: 4.89 +- 0.63 [%] POL ANG: -78.69 +- 3.65 [deg] +- 1.46 [%] +- 7.81 [deg] debiased polarisation degrees pixel 1 DEBIASED POL DEG: 7.52 [%] pixel 2 DEBIASED POL DEG: 7.96 [%] pixel 3 DEBIASED POL DEG: 7.46 [%] pixel 4 DEBIASED POL DEG: 4.85 [%] file = hr5340ins_440_160.pol polarisation calculation done for detector C200 derivation of INSTRUMENTAL POLARISATION source name: HR 5340 signal file used: hr5340ins_440_160.dat number of polariser cycles: 2 INPUT SIGNALS: polariser cycle no. 1: pixel pol. orientation source signal background signal [deg] [mV/s] [mV/s] 1 0 201.7750 0.0000 1 120 220.4050 0.0000 1 240 204.6020 0.0000 2 0 167.4900 0.0000 2 120 187.4760 0.0000 2 240 182.4830 0.0000 3 0 166.5210 0.0000 3 120 170.3150 0.0000 3 240 160.0440 0.0000 4 0 144.4450 0.0000 4 120 147.9100 0.0000 4 240 143.0470 0.0000 polariser cycle no. 2: pixel pol. orientation source signal background signal [deg] [mV/s] [mV/s] 1 0 204.5580 0.0000 1 120 217.9540 0.0000 1 240 203.6710 0.0000 2 0 167.8490 0.0000 2 120 189.9930 0.0000 2 240 190.3770 0.0000 3 0 165.7210 0.0000 3 120 169.4660 0.0000 3 240 158.1180 0.0000 4 0 144.5220 0.0000 4 120 149.8310 0.0000 4 240 144.5640 0.0000 average signals of all polariser cycles: pixel pol. orientation source signal background signal [deg] [mV/s] [mV/s] 1 0 203.1665 0.0000 1 120 219.1795 0.0000 1 240 204.1365 0.0000 2 0 167.6695 0.0000 2 120 188.7345 0.0000 2 240 186.4300 0.0000 3 0 166.1210 0.0000 3 120 169.8905 0.0000 3 240 159.0810 0.0000 4 0 144.4835 0.0000 4 120 148.8705 0.0000 4 240 143.8055 0.0000 standard deviation of source and background signal pixel dsig dback [mV/s] [mV/s] 1 1.2091 0.0000 2 2.6226 0.0000 3 0.7121 0.0000 4 0.7744 0.0000 S/N ratios for on- and off-position and source and source-to-background contrast pixel S/N_on S/N_off S/N_sour source/back contrast 1 172.71 0.00 0.00 0.0000 2 68.99 0.00 0.00 0.0000 3 231.76 0.00 0.00 0.0000 4 188.16 0.00 0.00 0.0000 POLARISATION DEGREE AND ANGLE: first error = Gaussian error second error = maximum error polariser cycle no. 1 pixel 1 POL DEG: 6.17 +- 0.55 [%] POL ANG: -64.05 +- 2.53 [deg] +- 1.35 [%] +- 6.35 [deg] pixel 2 POL DEG: 7.45 +- 1.35 [%] POL ANG: -83.06 +- 5.12 [deg] +- 2.91 [%] +- 9.65 [deg] pixel 3 POL DEG: 4.02 +- 0.41 [%] POL ANG: -40.71 +- 2.78 [deg] +- 0.79 [%] +- 5.39 [deg] pixel 4 POL DEG: 2.21 +- 0.49 [%] POL ANG: -51.90 +- 6.27 [deg] +- 0.94 [%] +- 12.56 [deg] polariser cycle no. 2 pixel 1 POL DEG: 4.92 +- 0.54 [%] POL ANG: -58.42 +- 3.11 [deg] +- 1.24 [%] +- 7.32 [deg] pixel 2 POL DEG: 9.05 +- 1.34 [%] POL ANG: 89.58 +- 4.12 [deg] +- 2.59 [%] +- 5.97 [deg] pixel 3 POL DEG: 4.51 +- 0.42 [%] POL ANG: -39.45 +- 2.51 [deg] +- 0.84 [%] +- 5.09 [deg] pixel 4 POL DEG: 2.68 +- 0.49 [%] POL ANG: -60.20 +- 5.17 [deg] +- 1.09 [%] +- 11.88 [deg] average values pixel 1 POL DEG: 5.52 +- 0.54 [%] POL ANG: -61.55 +- 2.80 [deg] +- 1.31 [%] +- 6.86 [deg] pixel 2 POL DEG: 8.19 +- 1.34 [%] POL ANG: -87.14 +- 4.60 [deg] +- 2.71 [%] +- 7.49 [deg] pixel 3 POL DEG: 4.27 +- 0.42 [%] POL ANG: -40.05 +- 2.64 [deg] +- 0.82 [%] +- 5.23 [deg] pixel 4 POL DEG: 2.42 +- 0.49 [%] POL ANG: -56.46 +- 5.73 [deg] +- 1.03 [%] +- 12.52 [deg] debiased polarisation degrees pixel 1 DEBIASED POL DEG: 5.49 [%] pixel 2 DEBIASED POL DEG: 8.08 [%] pixel 3 DEBIASED POL DEG: 4.25 [%] pixel 4 DEBIASED POL DEG: 2.37 [%] file = 3c279off_583_160.pol polarisation calculation done for detector C200 derivation of INSTRUMENTAL POLARISATION source name: 3C 279 background signal file used: 3c279off_583_160.dat number of polariser cycles: 2 INPUT SIGNALS: polariser cycle no. 1: pixel pol. orientation source signal background signal [deg] [mV/s] [mV/s] 1 0 92.5406 0.0000 1 120 97.8266 0.0000 1 240 91.2814 0.0000 2 0 74.9207 0.0000 2 120 79.0803 0.0000 2 240 80.6280 0.0000 3 0 74.2678 0.0000 3 120 74.4030 0.0000 3 240 70.2750 0.0000 4 0 62.2936 0.0000 4 120 66.2594 0.0000 4 240 66.2418 0.0000 polariser cycle no. 2: pixel pol. orientation source signal background signal [deg] [mV/s] [mV/s] 1 0 92.4645 0.0000 1 120 96.8529 0.0000 1 240 90.9352 0.0000 2 0 76.7913 0.0000 2 120 81.9175 0.0000 2 240 83.7336 0.0000 3 0 74.5604 0.0000 3 120 75.6450 0.0000 3 240 69.7583 0.0000 4 0 64.0274 0.0000 4 120 67.8958 0.0000 4 240 67.5836 0.0000 average signals of all polariser cycles: pixel pol. orientation source signal background signal [deg] [mV/s] [mV/s] 1 0 92.5026 0.0000 1 120 97.3398 0.0000 1 240 91.1083 0.0000 2 0 75.8560 0.0000 2 120 80.4989 0.0000 2 240 82.1808 0.0000 3 0 74.4141 0.0000 3 120 75.0240 0.0000 3 240 70.0167 0.0000 4 0 63.1605 0.0000 4 120 67.0776 0.0000 4 240 66.9127 0.0000 standard deviation of source and background signal pixel dsig dback [mV/s] [mV/s] 1 0.3277 0.0000 2 1.4558 0.0000 3 0.4353 0.0000 4 0.8651 0.0000 S/N ratios for on- and off-position and source and source-to-background contrast pixel S/N_on S/N_off S/N_sour source/back contrast 1 285.80 0.00 0.00 0.0000 2 54.62 0.00 0.00 0.0000 3 168.04 0.00 0.00 0.0000 4 75.96 0.00 0.00 0.0000 POLARISATION DEGREE AND ANGLE: first error = Gaussian error second error = maximum error polariser cycle no. 1 pixel 1 POL DEG: 4.75 +- 0.35 [%] POL ANG: -54.78 +- 1.96 [deg] +- 0.77 [%] +- 4.51 [deg] pixel 2 POL DEG: 4.84 +- 1.70 [%] POL ANG: 82.41 +- 10.00 [deg] +- 3.54 [%] +- 18.67 [deg] pixel 3 POL DEG: 4.12 +- 0.55 [%] POL ANG: -30.83 +- 3.80 [deg] +- 1.26 [%] +- 8.87 [deg] pixel 4 POL DEG: 4.51 +- 1.22 [%] POL ANG: -89.90 +- 7.67 [deg] +- 2.19 [%] +- 10.91 [deg] polariser cycle no. 2 pixel 1 POL DEG: 4.22 +- 0.34 [%] POL ANG: -52.80 +- 2.19 [deg] +- 0.73 [%] +- 4.77 [deg] pixel 2 POL DEG: 5.72 +- 1.64 [%] POL ANG: 82.70 +- 8.20 [deg] +- 3.46 [%] +- 15.30 [deg] pixel 3 POL DEG: 5.48 +- 0.56 [%] POL ANG: -34.99 +- 2.85 [deg] +- 1.23 [%] +- 6.41 [deg] pixel 4 POL DEG: 4.15 +- 1.19 [%] POL ANG: -87.92 +- 8.16 [deg] +- 2.24 [%] +- 12.66 [deg] average values pixel 1 POL DEG: 4.48 +- 0.35 [%] POL ANG: -53.85 +- 2.07 [deg] +- 0.75 [%] +- 4.64 [deg] pixel 2 POL DEG: 5.29 +- 1.67 [%] POL ANG: 82.57 +- 9.01 [deg] +- 3.50 [%] +- 16.81 [deg] pixel 3 POL DEG: 4.79 +- 0.56 [%] POL ANG: -33.21 +- 3.27 [deg] +- 1.24 [%] +- 7.48 [deg] pixel 4 POL DEG: 4.33 +- 1.20 [%] POL ANG: -88.94 +- 7.91 [deg] +- 2.21 [%] +- 11.76 [deg] debiased polarisation degrees pixel 1 DEBIASED POL DEG: 4.47 [%] pixel 2 DEBIASED POL DEG: 5.02 [%] pixel 3 DEBIASED POL DEG: 4.76 [%] pixel 4 DEBIASED POL DEG: 4.15 [%] file = hr5340off_587_160.pol polarisation calculation done for detector C200 derivation of INSTRUMENTAL POLARISATION source name: HR 5340 background signal file used: hr5340off_587_160.dat number of polariser cycles: 2 INPUT SIGNALS: polariser cycle no. 1: pixel pol. orientation source signal background signal [deg] [mV/s] [mV/s] 1 0 76.2923 0.0000 1 120 81.9219 0.0000 1 240 73.0611 0.0000 2 0 61.6722 0.0000 2 120 66.2709 0.0000 2 240 63.1625 0.0000 3 0 61.8904 0.0000 3 120 65.4024 0.0000 3 240 55.7449 0.0000 4 0 52.0929 0.0000 4 120 55.6276 0.0000 4 240 52.0331 0.0000 polariser cycle no. 2: pixel pol. orientation source signal background signal [deg] [mV/s] [mV/s] 1 0 74.6230 0.0000 1 120 82.2792 0.0000 1 240 72.0568 0.0000 2 0 60.8583 0.0000 2 120 67.0658 0.0000 2 240 65.7023 0.0000 3 0 60.7775 0.0000 3 120 65.1266 0.0000 3 240 55.7878 0.0000 4 0 53.4590 0.0000 4 120 57.0129 0.0000 4 240 54.3562 0.0000 average signals of all polariser cycles: pixel pol. orientation source signal background signal [deg] [mV/s] [mV/s] 1 0 75.4576 0.0000 1 120 82.1005 0.0000 1 240 72.5590 0.0000 2 0 61.2653 0.0000 2 120 66.6684 0.0000 2 240 64.4324 0.0000 3 0 61.3340 0.0000 3 120 65.2645 0.0000 3 240 55.7663 0.0000 4 0 52.7760 0.0000 4 120 56.3203 0.0000 4 240 53.1947 0.0000 standard deviation of source and background signal pixel dsig dback [mV/s] [mV/s] 1 0.6263 0.0000 2 0.8801 0.0000 3 0.3628 0.0000 4 0.9582 0.0000 S/N ratios for on- and off-position and source and source-to-background contrast pixel S/N_on S/N_off S/N_sour source/back contrast 1 122.47 0.00 0.00 0.0000 2 72.86 0.00 0.00 0.0000 3 167.54 0.00 0.00 0.0000 4 56.45 0.00 0.00 0.0000 POLARISATION DEGREE AND ANGLE: first error = Gaussian error second error = maximum error polariser cycle no. 1 pixel 1 POL DEG: 7.46 +- 0.78 [%] POL ANG: -49.44 +- 2.84 [deg] +- 1.53 [%] +- 5.55 [deg] pixel 2 POL DEG: 4.73 +- 1.26 [%] POL ANG: -69.26 +- 7.63 [deg] +- 2.93 [%] +- 17.61 [deg] pixel 3 POL DEG: 10.28 +- 0.64 [%] POL ANG: -40.53 +- 1.52 [deg] +- 1.29 [%] +- 3.10 [deg] pixel 4 POL DEG: 4.96 +- 1.64 [%] POL ANG: -59.59 +- 9.45 [deg] +- 3.57 [%] +- 21.20 [deg] polariser cycle no. 2 pixel 1 POL DEG: 8.94 +- 0.80 [%] POL ANG: -53.02 +- 2.41 [deg] +- 1.72 [%] +- 5.31 [deg] pixel 2 POL DEG: 6.49 +- 1.26 [%] POL ANG: -83.97 +- 5.47 [deg] +- 2.65 [%] +- 9.97 [deg] pixel 3 POL DEG: 9.90 +- 0.64 [%] POL ANG: -43.87 +- 1.57 [deg] +- 1.19 [%] +- 2.74 [deg] pixel 4 POL DEG: 4.32 +- 1.59 [%] POL ANG: -67.03 +- 10.53 [deg] +- 3.62 [%] +- 24.11 [deg] average values pixel 1 POL DEG: 8.18 +- 0.79 [%] POL ANG: -51.39 +- 2.61 [deg] +- 1.63 [%] +- 5.45 [deg] pixel 2 POL DEG: 5.43 +- 1.26 [%] POL ANG: -77.85 +- 6.59 [deg] +- 2.83 [%] +- 13.89 [deg] pixel 3 POL DEG: 10.07 +- 0.64 [%] POL ANG: -42.16 +- 1.55 [deg] +- 1.25 [%] +- 2.94 [deg] pixel 4 POL DEG: 4.59 +- 1.61 [%] POL ANG: -63.11 +- 10.05 [deg] +- 3.62 [%] +- 22.97 [deg] debiased polarisation degrees pixel 1 DEBIASED POL DEG: 8.14 [%] pixel 2 DEBIASED POL DEG: 5.29 [%] pixel 3 DEBIASED POL DEG: 10.05 [%] pixel 4 DEBIASED POL DEG: 4.30 [%] file = hr5340ins_587_160.pol polarisation calculation done for detector C200 derivation of INSTRUMENTAL POLARISATION source name: HR 5340 signal file used: hr5340ins_587_160.dat number of polariser cycles: 2 INPUT SIGNALS: polariser cycle no. 1: pixel pol. orientation source signal background signal [deg] [mV/s] [mV/s] 1 0 96.5096 0.0000 1 120 99.6163 0.0000 1 240 93.6226 0.0000 2 0 78.4217 0.0000 2 120 84.4508 0.0000 2 240 85.4118 0.0000 3 0 79.4471 0.0000 3 120 81.4942 0.0000 3 240 74.2467 0.0000 4 0 71.9113 0.0000 4 120 77.0900 0.0000 4 240 73.7187 0.0000 polariser cycle no. 2: pixel pol. orientation source signal background signal [deg] [mV/s] [mV/s] 1 0 95.0937 0.0000 1 120 107.5050 0.0000 1 240 98.6060 0.0000 2 0 79.1729 0.0000 2 120 85.9428 0.0000 2 240 86.6742 0.0000 3 0 80.2487 0.0000 3 120 80.0458 0.0000 3 240 75.0216 0.0000 4 0 73.5193 0.0000 4 120 78.3039 0.0000 4 240 75.4619 0.0000 average signals of all polariser cycles: pixel pol. orientation source signal background signal [deg] [mV/s] [mV/s] 1 0 95.8017 0.0000 1 120 103.5607 0.0000 1 240 96.1143 0.0000 2 0 78.7973 0.0000 2 120 85.1968 0.0000 2 240 86.0430 0.0000 3 0 79.8479 0.0000 3 120 80.7700 0.0000 3 240 74.6341 0.0000 4 0 72.7153 0.0000 4 120 77.6970 0.0000 4 240 74.5903 0.0000 standard deviation of source and background signal pixel dsig dback [mV/s] [mV/s] 1 2.9845 0.0000 2 0.6621 0.0000 3 0.5780 0.0000 4 0.8425 0.0000 S/N ratios for on- and off-position and source and source-to-background contrast pixel S/N_on S/N_off S/N_sour source/back contrast 1 33.00 0.00 0.00 0.0000 2 125.88 0.00 0.00 0.0000 3 135.67 0.00 0.00 0.0000 4 89.02 0.00 0.00 0.0000 POLARISATION DEGREE AND ANGLE: first error = Gaussian error second error = maximum error polariser cycle no. 1 pixel 1 POL DEG: 3.98 +- 2.81 [%] POL ANG: -45.61 +- 20.17 [deg] +- 4.32 [%] +- 33.61 [deg] pixel 2 POL DEG: 5.87 +- 0.75 [%] POL ANG: 86.36 +- 3.54 [deg] +- 1.55 [%] +- 6.00 [deg] pixel 3 POL DEG: 6.11 +- 0.70 [%] POL ANG: -37.95 +- 3.15 [deg] +- 1.43 [%] +- 6.59 [deg] pixel 4 POL DEG: 4.54 +- 1.04 [%] POL ANG: -70.06 +- 6.53 [deg] +- 2.43 [%] +- 15.11 [deg] polariser cycle no. 2 pixel 1 POL DEG: 8.18 +- 2.71 [%] POL ANG: -67.97 +- 9.48 [deg] +- 6.33 [%] +- 22.14 [deg] pixel 2 POL DEG: 6.32 +- 0.75 [%] POL ANG: 87.47 +- 3.25 [deg] +- 1.51 [%] +- 5.24 [deg] pixel 3 POL DEG: 4.84 +- 0.68 [%] POL ANG: -29.02 +- 4.00 [deg] +- 1.58 [%] +- 9.49 [deg] pixel 4 POL DEG: 4.08 +- 1.01 [%] POL ANG: -71.91 +- 7.12 [deg] +- 2.35 [%] +- 16.15 [deg] average values pixel 1 POL DEG: 5.72 +- 2.75 [%] POL ANG: -61.02 +- 13.78 [deg] +- 6.04 [%] +- 31.02 [deg] pixel 2 POL DEG: 6.10 +- 0.75 [%] POL ANG: 86.94 +- 3.39 [deg] +- 1.53 [%] +- 5.60 [deg] pixel 3 POL DEG: 5.41 +- 0.69 [%] POL ANG: -34.01 +- 3.57 [deg] +- 1.51 [%] +- 8.04 [deg] pixel 4 POL DEG: 4.30 +- 1.02 [%] POL ANG: -70.94 +- 6.82 [deg] +- 2.39 [%] +- 15.63 [deg] debiased polarisation degrees pixel 1 DEBIASED POL DEG: 5.02 [%] pixel 2 DEBIASED POL DEG: 6.05 [%] pixel 3 DEBIASED POL DEG: 5.37 [%] pixel 4 DEBIASED POL DEG: 4.18 [%] file = hr5340pix3ins_587_160.pol polarisation calculation done for detector C200 derivation of INSTRUMENTAL POLARISATION source name: HR 5340 signal file used: hr5340pix3ins_587_160.dat number of polariser cycles: 2 INPUT SIGNALS: polariser cycle no. 1: pixel pol. orientation source signal background signal [deg] [mV/s] [mV/s] 1 0 83.8139 0.0000 1 120 93.6744 0.0000 1 240 84.0654 0.0000 2 0 65.0063 0.0000 2 120 66.8582 0.0000 2 240 66.4649 0.0000 3 0 64.9232 0.0000 3 120 65.2348 0.0000 3 240 58.3609 0.0000 4 0 147.4700 0.0000 4 120 159.2310 0.0000 4 240 153.3430 0.0000 polariser cycle no. 2: pixel pol. orientation source signal background signal [deg] [mV/s] [mV/s] 1 0 86.3673 0.0000 1 120 91.3850 0.0000 1 240 84.9389 0.0000 2 0 63.4164 0.0000 2 120 66.4318 0.0000 2 240 67.3250 0.0000 3 0 62.8528 0.0000 3 120 65.3737 0.0000 3 240 58.3213 0.0000 4 0 146.5610 0.0000 4 120 158.0150 0.0000 4 240 155.8230 0.0000 average signals of all polariser cycles: pixel pol. orientation source signal background signal [deg] [mV/s] [mV/s] 1 0 85.0906 0.0000 1 120 92.5297 0.0000 1 240 84.5022 0.0000 2 0 64.2113 0.0000 2 120 66.6450 0.0000 2 240 66.8950 0.0000 3 0 63.8880 0.0000 3 120 65.3043 0.0000 3 240 58.3411 0.0000 4 0 147.0155 0.0000 4 120 158.6230 0.0000 4 240 154.5830 0.0000 standard deviation of source and background signal pixel dsig dback [mV/s] [mV/s] 1 1.1191 0.0000 2 0.5873 0.0000 3 0.6563 0.0000 4 0.9195 0.0000 S/N ratios for on- and off-position and source and source-to-background contrast pixel S/N_on S/N_off S/N_sour source/back contrast 1 78.07 0.00 0.00 0.0000 2 112.23 0.00 0.00 0.0000 3 95.25 0.00 0.00 0.0000 4 166.83 0.00 0.00 0.0000 POLARISATION DEGREE AND ANGLE: first error = Gaussian error second error = maximum error polariser cycle no. 1 pixel 1 POL DEG: 8.27 +- 1.19 [%] POL ANG: -60.65 +- 4.08 [deg] +- 2.78 [%] +- 9.76 [deg] pixel 2 POL DEG: 1.89 +- 0.81 [%] POL ANG: -84.19 +- 12.20 [deg] +- 1.60 [%] +- 21.38 [deg] pixel 3 POL DEG: 7.93 +- 0.97 [%] POL ANG: -31.15 +- 3.47 [deg] +- 2.25 [%] +- 8.24 [deg] pixel 4 POL DEG: 4.92 +- 0.56 [%] POL ANG: -74.98 +- 3.22 [deg] +- 1.35 [%] +- 7.44 [deg] polariser cycle no. 2 pixel 1 POL DEG: 4.96 +- 1.17 [%] POL ANG: -53.91 +- 6.71 [deg] +- 2.37 [%] +- 14.08 [deg] pixel 2 POL DEG: 4.00 +- 0.82 [%] POL ANG: 83.71 +- 5.82 [deg] +- 1.71 [%] +- 10.60 [deg] pixel 3 POL DEG: 7.37 +- 0.99 [%] POL ANG: -40.33 +- 3.73 [deg] +- 1.91 [%] +- 7.25 [deg] pixel 4 POL DEG: 5.08 +- 0.57 [%] POL ANG: -84.81 +- 3.07 [deg] +- 1.21 [%] +- 5.56 [deg] average values pixel 1 POL DEG: 6.57 +- 1.18 [%] POL ANG: -58.12 +- 5.10 [deg] +- 2.62 [%] +- 11.64 [deg] pixel 2 POL DEG: 2.89 +- 0.81 [%] POL ANG: 87.59 +- 8.03 [deg] +- 1.53 [%] +- 12.62 [deg] pixel 3 POL DEG: 7.55 +- 0.98 [%] POL ANG: -35.55 +- 3.64 [deg] +- 2.11 [%] +- 8.01 [deg] pixel 4 POL DEG: 4.93 +- 0.56 [%] POL ANG: -79.98 +- 3.19 [deg] +- 1.29 [%] +- 6.70 [deg] debiased polarisation degrees pixel 1 DEBIASED POL DEG: 6.46 [%] pixel 2 DEBIASED POL DEG: 2.77 [%] pixel 3 DEBIASED POL DEG: 7.49 [%] pixel 4 DEBIASED POL DEG: 4.90 [%]