#This routine takes a flat-fielded image (Fy...), and creates an image 
#suitable for doing photometry (Py...).  It uses the bad pixel mask
#"img" to set bad regions to 50,000, so that
#the photometry routines won't try to do photometery there
#(assuming DATAMAX=38000 or some such).
# "photometric" image,
#task y4kfix=/home/massey/survey/y4kfix.cl
#Identify objects
#changed F--->S (sky corrected)
#Changed S--->G (shutter corrected)
procedure y4kfix(img)
    string img {prompt="bad pixel mask"}
begin
     string bad,s1
#Get parameter
       bad=img
delete("objs")
hselect("%G%%y*.fits","$I","imgtype='OBJECT'",>"objs")
imdelete("P"//"@objs")
list="objs"
while (fscan(list,s1) !=EOF) {
imexpr("b !=0 ? 50000 : a","P"//s1,"G"//s1,bad)
}
end