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Hubble Space Telescope
IR Encircled Energy

Table of Contents

Overview

November 2009: Following its alignment to the HST OTA, IR point spread function measurements of ~130 stars over the field were made in the F098M, F105W and F160W and compared to model computations and CEI specifications. Deep, core-saturated images of a standard star, sampling the field at 5 locations, were also obtained to evaluate the PSF wings. All encircled energy specifications are met or exceeded, with exception of the inner core EE at 160 nm, as expected from previous ground testing and modeling results. The optical model has been correlated to the observed PSF properties and may be used to predict performance over the full IR spectral range.


For more details, see ISR 2009-37.

Tables

WFC3/IR PSF Encircled Energy Fraction vs. Aperture Radius (arcsec). The first column in the table is the aperture radius. The second through 11th columns are the EE fractions at 0.7 to 1.7 microns in 0.1 micron increments.

wl(um): 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7
0.10 0.575 0.549 0.524 0.502 0.484 0.468 0.453 0.438 0.426 0.410 0.394
0.15 0.736 0.714 0.685 0.653 0.623 0.596 0.575 0.558 0.550 0.539 0.531
0.20 0.802 0.794 0.780 0.762 0.739 0.712 0.683 0.653 0.631 0.608 0.590
0.25 0.831 0.827 0.821 0.813 0.804 0.792 0.776 0.756 0.735 0.708 0.679
0.30 0.850 0.845 0.838 0.833 0.828 0.822 0.816 0.808 0.803 0.789 0.770
0.40 0.878 0.876 0.869 0.859 0.850 0.845 0.841 0.838 0.840 0.836 0.832
0.50 0.899 0.894 0.889 0.884 0.878 0.868 0.858 0.852 0.854 0.850 0.848
0.60 0.916 0.913 0.904 0.897 0.893 0.889 0.883 0.875 0.870 0.863 0.859
0.80 0.937 0.936 0.929 0.924 0.918 0.909 0.903 0.900 0.903 0.900 0.895
1.00 0.951 0.951 0.946 0.941 0.935 0.930 0.925 0.920 0.917 0.912 0.909
1.50 0.967 0.969 0.967 0.965 0.963 0.959 0.954 0.951 0.952 0.948 0.943
2.00 0.974 0.977 0.976 0.975 0.973 0.972 0.969 0.967 0.970 0.967 0.963