Changes between Initial Version and Version 1 of PS1_GPC1_Rotator_20080930

Timestamp:

Mar 2, 2009, 8:56:34 AM (17 years ago)

Author:

eugene

Comment:

--

PS1_GPC1_Rotator_20080930

@@ +1 @@
+I've performed my analysis of the fitted vs observed boresite
+positions for the 20080915 data that JT was discussing a bit today.
+I've done the same fits as before: modeling the path of the boresite
+offset as an ellipse.  The boresite offset is defined to be the
+distance in pixels that the boresite coordinate is shifted  relative
+to the center of the camera (midway between ota 33 cell 00 pixel 00
+and ota 44 cell 00 pixel 00).  I've cleaned up the plot to show in one
+graph the path in X,Y coordinates as well as the following values vs
+position angle: the X-offset, the Y-offset, the X-offset residual, and
+the Y-offset residual.  The residuals are the difference between the
+observed offset and the fit to the elliptical model.  Per confusion
+from Jeff, I've adjusted plot of the path to have an aspect ratio of 1
+and a fixed scale for all of the attached plots (220x220 pixels).
+I've also added a mark to represent on the path the position for which
+the rotator was closest to -115.
+
+Attached are plots for the g & r sequences from 20080915 and the i
+sequence from 20080827.  The quality of the astrometry solutions was
+worse for 20080915: there were fewer stars in these fields, and I've
+had to reject a few points that were seriously outside the observed
+trends.  Below are the fitted ellipse parameters for each data set.
+My initial impressions are:
+
+1) g & i both seem to confirm the trend that the boresite error in the
+X direction gets larger for lower altitude, but that the in the Y
+direction it is generally constant.  for the altitudes 70, 50, 30:
+RX(g) = 52, 77, 92; RX(i) = 75, 108, 145;  RY(g) = 39,45,55; RY(i) =
+53, 59, 67.  So, some growth in the Y-direction, but much less than in
+X.
+
+2) the r-band data, taken the same night as the g-band data does not
+agree well with these trends: RX(r) = 45, 43, 60; RY(r) = 48, 59, 88.
+It seems that for this r-band sequence, the trend is flipped (X nearly
+constant, Y grows with decreasing altitude).
+
+any one else have other thoughts?  this does not seem to be a simple
+trend of the offset as a function of rotator angle and altitude...
+
+gene
+
+==> rotseq.30g.pars <==
+# fitted values:
+Xo:  18.828287
+Yo:  -71.378357
+RX:  -92.772423
+RY:  55.671108
+P0:  0.660415
+T0:  -0.036934
+
+==> rotseq.50g.pars <==
+# fitted values:
+Xo:  -24.885120
+Yo:  -52.015652
+RX:  -77.185303
+RY:  45.916832
+P0:  -2.276575
+T0:  3.251292
+
+==> rotseq.70g.pars <==
+# fitted values:
+Xo:  -64.563072
+Yo:  -4.641876
+RX:  -52.212910
+RY:  39.014824
+P0:  -1.914627
+T0:  3.266521
+
+
+==> rotseq.30r.pars <==
+# fitted values:
+Xo:  -71.361954
+Yo:  33.617271
+RX:  -45.239864
+RY:  88.274780
+P0:  1.339565
+T0:  0.634835
+
+==> rotseq.50r.pars <==
+# fitted values:
+Xo:  -48.113983
+Yo:  27.144241
+RX:  -43.854301
+RY:  59.156593
+P0:  0.679057
+T0:  -0.143105
+
+==> rotseq.70r.pars <==
+# fitted values:
+Xo:  -16.860861
+Yo:  80.069687
+RX:  -60.495838
+RY:  48.157955
+P0:  0.831692
+T0:  -0.456550
+
+
+==> rotseq.30i.pars <==
+# fitted values:
+Xo:  45.276226
+Yo:  -9.302369
+RX:  145.009399
+RY:  67.481323
+P0:  0.646368
+T0:  0.357436
+
+==> rotseq.50i.pars <==
+# fitted values:
+Xo:  21.140253
+Yo:  -14.027385
+RX:  108.704620
+RY:  59.530045
+P0:  0.587284
+T0:  0.475980
+
+==> rotseq.70i.pars <==
+# fitted values:
+Xo:  10.799455
+Yo:  -14.946228
+RX:  75.923737
+RY:  53.394173
+P0:  1.152103
+T0:  0.182733