# The following file is from Jim Gunn, from June 2001. It should be # self-explanatory; for most purposes, you will want to use the second # column. Consider this file preliminary. # # These filter curves have been used to calculate the effective # wavelengths and the qtdl/l (see Chapter 8 of the Black Book) of the # filters; the values are: # # u 3551 0.0171 # g 4686 0.0893 # r 6166 0.0886 # i 7480 0.0591 # z 8932 0.0099 # # Table Caption For Response Functions # # The first column is the wavelength in \AAngstroms. The second column # (respt) is the quantum efficiency on the sky looking through 1.3 # airmasses at APO for a point source. The third column (resbig) is the # QE under these conditions for very large sources (size greater than # about 80 pixels) for which the infrared scattering is negligible. The # only filters for which the infrared scattering has any effect are r and # i; the scattering in the bluer chips is negligible, and the z chips are # not thinned and the phenomenon does not exist. The fourth column # (resnoa) is the response of the third column with {\it no} atmosphere, # and the fifth column is the assumed atmospheric transparency at {\it # one} airmass at APO. The tables were constructed using monochromator # illumination of the camera with a bandpass of about 100 \AA, sampled for # the u filter at 50 \AA intervals and for the others at 100 \AA # intervals. These measurements were compared with measured responses of # the component filters and detectors and three additional points were # interpolated using these data, two at the extreme toes and one # additional (in g, r, and i) at the point of the beginning of the sharp # cutoff of the shortpass interference filter. These points are necessary # in order to make spline interpolation of the response data well-behaved. # These spline-interpolated response data were then multiplied by measured # aluminum reflectivities and scaled atmospheric transmission to produce # the tables below. The overall normalization is somewhat uncertain, # but this uncertainty does not affect the shapes. Note, however, that # there has been no attempt to remove the finite resolution of the # monochromator measurements. These tables are the {\it averages} of the # responses for all six of the camera chips with a given filter. The # responses are in general very similar except in the z band, where the # nonuniformity of the infrared rolloff, presumably associated with # varying thickness of the epitaxial layer or perhaps the gate structures # in these thick devices, introduces variations in the effective wavelengths # of the filters of order 100 \AA. We are currently working on better # response functions and will present them when they become available, but # these will suffice for most applications. In all cases the first point # is a measured point, so the grid of wavelengths at which measurements # exist is a subset of the wavelength lists here. # # SDSS Camera i Response Function 89 Points # # lam respt resbig resnoa xatm 6430 0.0000 0.0000 0.0000 0.9346 6455 0.0001 0.0001 0.0001 0.9354 6480 0.0003 0.0003 0.0003 0.9363 6505 0.0004 0.0004 0.0004 0.9373 6530 0.0004 0.0004 0.0005 0.9385 6555 0.0003 0.0004 0.0004 0.9395 6580 0.0003 0.0003 0.0003 0.9400 6605 0.0004 0.0004 0.0005 0.9398 6630 0.0009 0.0009 0.0010 0.9386 6655 0.0019 0.0019 0.0021 0.9366 6680 0.0034 0.0034 0.0036 0.9349 6705 0.0056 0.0056 0.0060 0.9345 6730 0.0103 0.0104 0.0111 0.9366 6755 0.0194 0.0197 0.0208 0.9421 6780 0.0344 0.0349 0.0366 0.9492 6805 0.0561 0.0569 0.0597 0.9494 6830 0.0839 0.0851 0.0913 0.9334 6855 0.1164 0.1181 0.1317 0.9057 6880 0.1528 0.1552 0.1779 0.8862 6905 0.1948 0.1980 0.2260 0.8893 6930 0.2408 0.2448 0.2719 0.9083 6955 0.2857 0.2906 0.3125 0.9311 6980 0.3233 0.3290 0.3470 0.9450 7005 0.3503 0.3566 0.3755 0.9464 7030 0.3759 0.3829 0.3978 0.9561 7055 0.3990 0.4067 0.4142 0.9709 7080 0.4162 0.4245 0.4256 0.9826 7105 0.4233 0.4320 0.4331 0.9827 7130 0.4165 0.4252 0.4377 0.9629 7155 0.3943 0.4028 0.4405 0.9192 7180 0.3760 0.3844 0.4416 0.8849 7205 0.3823 0.3911 0.4411 0.8974 7230 0.3918 0.4011 0.4392 0.9182 7255 0.3892 0.3988 0.4358 0.9195 7280 0.3828 0.3924 0.4315 0.9153 7305 0.3820 0.3919 0.4265 0.9225 7330 0.3884 0.3988 0.4214 0.9436 7355 0.3872 0.3979 0.4165 0.9505 7380 0.3821 0.3930 0.4119 0.9496 7405 0.3787 0.3898 0.4077 0.9512 7430 0.3759 0.3872 0.4039 0.9531 7455 0.3727 0.3842 0.4006 0.9535 7480 0.3681 0.3799 0.3975 0.9508 7505 0.3618 0.3737 0.3943 0.9449 7530 0.3565 0.3685 0.3906 0.9416 7555 0.3554 0.3678 0.3862 0.9483 7580 0.3478 0.3603 0.3812 0.9429 7605 0.1473 0.1527 0.3757 0.4926 7630 0.2096 0.2176 0.3700 0.6546 7655 0.2648 0.2752 0.3641 0.7939 7680 0.3300 0.3434 0.3583 0.9530 7705 0.3256 0.3392 0.3526 0.9558 7730 0.3223 0.3361 0.3473 0.9602 7755 0.3179 0.3319 0.3424 0.9615 7780 0.3129 0.3272 0.3379 0.9605 7805 0.3077 0.3221 0.3337 0.9583 7830 0.3026 0.3173 0.3297 0.9559 7855 0.2980 0.3129 0.3259 0.9541 7880 0.2944 0.3095 0.3224 0.9541 7905 0.2921 0.3077 0.3194 0.9567 7930 0.2916 0.3075 0.3169 0.9622 7955 0.2921 0.3086 0.3150 0.9692 7980 0.2927 0.3098 0.3132 0.9762 8005 0.2923 0.3098 0.3111 0.9814 8030 0.2896 0.3076 0.3081 0.9833 8055 0.2840 0.3021 0.3039 0.9801 8080 0.2758 0.2939 0.2996 0.9702 8105 0.2642 0.2821 0.2945 0.9524 8130 0.2427 0.2597 0.2803 0.9285 8155 0.2091 0.2242 0.2493 0.9075 8180 0.1689 0.1815 0.2060 0.8931 8205 0.1276 0.1374 0.1578 0.8853 8230 0.0901 0.0973 0.1118 0.8843 8255 0.0603 0.0652 0.0743 0.8902 8280 0.0378 0.0410 0.0458 0.9033 8305 0.0218 0.0237 0.0257 0.9242 8330 0.0117 0.0128 0.0134 0.9483 8355 0.0068 0.0074 0.0077 0.9591 8380 0.0048 0.0053 0.0055 0.9576 8405 0.0033 0.0036 0.0037 0.9567 8430 0.0020 0.0022 0.0023 0.9564 8455 0.0013 0.0014 0.0015 0.9565 8480 0.0010 0.0011 0.0011 0.9569 8505 0.0009 0.0010 0.0011 0.9576 8530 0.0009 0.0010 0.0011 0.9584 8555 0.0008 0.0009 0.0009 0.9592 8580 0.0005 0.0006 0.0006 0.9598 8605 0.0002 0.0003 0.0003 0.9602 8630 0.0000 0.0000 0.0000 0.9603