The IR detector field of view is nominally concentric with the UVIS field, but subtends a somewhat smaller area on the sky, 136×123 arcsec. The detector tilt is about the x-axis (AXIS1 in Figure 7.1
), so the projected aperture shape is nearly a rectangle, with the angle between the x- and y-axes on the sky nearly 90°
, as shown by the outline in Figure B.3
. At field center, the x- and y-scales are 0.135 and 0.121 arcsec/pixel, respectively. A vector plot of the deviation from linearity is given in Figure B.3
. The deviations have been magnified by a factor of 10, as in Figure B.1
. The largest deviation is 10 pixels, corresponding to about 1.4 arcsec.