# Definitions for SKYBLOCK algorithm. define SKBSKYMIN 10000 # Minimum number of sky pixels in subblock define SKBFRAC 0.66 # Frac of sky pix in subblock for sky estimate define SKBGROW 1.5 # Grow for rejected subblocks define SKBSIGBIN 2.5 # Sigma width of histogram define SKBA 0.01 # Histogram resolution define SKBNMINPIX 50 # Minimum number of pixels/subblock/side define SKBNMINBINS 500 # Minimum average bin population define SKBHISTWT 2 # Default histogram weighting power define SKBCNV "" # Convolution define SKB_STRLEN 99 # String length in parameters define SKB_LEN 82 # Sky block structure length # The following apply to all images. define SKB_BLKSTEP Memi[$1] # Step size define SKB_BLKSIZE Memi[$1+1] # Number of pixels or blocks define SKB_NSUBBLKS Memi[$1+2] # Number of subblocks per block define SKB_SKYMIN Memi[$1+3] # Minimum number of sky pixels define SKB_NMINPIX Memi[$1+4] # Min pixels/subblock/side define SKB_SIGBIN Memr[P2R($1+5)] # Histogram sigma limit define SKB_A Memr[P2R($1+6)] # Histogram resolution define SKB_B Memr[P2R($1+7)] # Bin start define SKB_NBINS Memi[$1+8] # Number of bins define SKB_NMINBINS Memi[$1+9] # Min avg bin population define SKB_HISTWT Memi[$1+10] # Histogram weighting power define SKB_SIGFAC Memr[P2R($1+11)] # Sigma correction factor define SKB_FRAC Memr[P2R($1+12)] # Frac of sky pix in subblock define SKB_GROW Memr[P2R($1+13)] # Grow for rejected subblocks define SKB_CNV P2C($1+14) # Pointer to convolution string (99) # The following are set for each image. define SKB_NCBLK Memi[$1+65] # Number of blocks across image define SKB_NLBLK Memi[$1+66] # Number of blocks across image define SKB_NCPIX Memi[$1+67] # Number of pixels in blocks define SKB_NLPIX Memi[$1+68] # Number of pixels in blocks define SKB_NCSBLK Memi[$1+69] # Number of subblocks across image define SKB_NLSBLK Memi[$1+70] # Number of subblocks across image define SKB_NCSPIX Memi[$1+71] # Number of pixels in subblocks define SKB_NLSPIX Memi[$1+72] # Number of pixels in subblocks define SKB_NSKYMIN Memi[$1+73] # Minimum pixels to evaluate histogram define SKB_BINS Memi[$1+74] # Pointer to bins define SKB_NAV Memi[$1+75] # Number of bins to average for weights define SKB_NSKY Memi[$1+76] # Pointer to num sky pix define SKB_EXP Memi[$1+77] # Pointer to exposure values define SKB_SKYS Memi[$1+78] # Pointer to sky block values define SKB_SIGS Memi[$1+79] # Pointer to sigma block values define SKB_SKY Memi[$1+80] # Pointer to current sky block line define SKB_SIG Memi[$1+81] # Pointer to current sigma block line