FourStar Linearity

Linearity correction maps are provided for each array for the FullWell mode and the LoNoise mode. The filename is divided into 3 parts: the order of polynomial, the gain setting and the chip number.

                                                                                                 lcX_YY_Z.fits
Linearity Correction "X"_______________________________|      |     |
                                    2 = 2nd order correction                                  |     |
                               "YY"__________________________________|     |
                                    fw = full well gain                                                 |
                                    lo = low-noise gain                                                |
                                 "Z"______________________________________|
                                     1 = Chip #1
                                     2 = Chip #2
                                     3 = Chip #3
                                     4 = Chip #4

corrected_counts = raw_counts * ( 1 + lc2_??_? * raw_counts)

In IRAF
cl> imexpr "a*(1+a*b)" output raw,lc2_??_?

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