; PROGRAM, dkrate
; This program calculates the dark count accumulation rate and the
; zero-time images.


cam=1
ccdt=cam
PRINT, 'Enter camera number'
READ, cam
PRINT,'Enter CCD temperature for desired mean dark images'
READ,ccdt
path=STRING(cam,cam,ccdt $
	   ,FORMAT='("/jasper/cnsr3_data1/dk/c",I1,"/dk",I1,".*s.mean.",I3,"C")')
flist=FINDFILE(path,COUNT=n)
expt=INTARR(n)
FOR j=0,n-1 DO BEGIN
    ts=STRPOS(flist(j),STRING(cam,FORMAT='("dk",I1,".")'))+4
    tl=STRPOS(flist(j),"s.mean")-ts
    expt(j)=FIX(STRMID(flist(j),ts,tl))
    ENDFOR
expt=expt(SORT(expt))
st = DBLARR(256,256)
sts = st
smi = st
smis = st
stmi = st

; summing exposure times and mean images over 1 - 180 second exposures
FOR j = 0,n-1 DO BEGIN
    texp=DOUBLE(expt(j))
    time = REPLICATE(texp,256,256)
    rdmeandk, cam,texp,mi 
    st = st + time
    sts = sts + time^2
    smi = smi + mi
    smis = smis + LONG(mi)^2
    tmp=time*mi
    hlp,tmp
    stmi = stmi + time * mi
    hlp,stmi
ENDFOR

M=DBLARR(256,256)
Q=M
P=M
corr = M
M = n * sts - st^2
Q = n * smis - smi^2
P = n * stmi - smi * st
rate = P / M
tzero = ((M  * FLOAT(smi) - P * st)/(n * M)) 
corr = P / SQRT(M*Q)
rate=rate>0
tzero=tzero>0
TVSCL, tzero<256, 0
TVSCL, tzero<256, 0
TVSCL, rate<10, 1
TVSCL, corr, 2

; save to 3 appropriately-named files under BYTE format.
rname=STRING(cam,cam,ccdt $
      ,FORMAT='("/jasper/cnsr3_data1/dk/c",I1,"/dk",I1,".rate.",I3,"C")')
OPENW,unit,rname,/GET_LUN
brate = BYTE((200 * rate)+0.5)
WRITEU,unit,brate
CLOSE,unit
FREE_LUN,unit

zname=STRING(cam,cam,ccdt $
      ,FORMAT='("/jasper/cnsr3_data1/dk/c",I1,"/dk",I1,".bias.",I3,"C")')
OPENW,unit,zname,/GET_LUN
btz=BYTE(tzero + .5)
WRITEU,unit,btz
CLOSE,unit
FREE_LUN,unit

cname = STRING(cam,cam,ccdt $
	,FORMAT='("/jasper/cnsr3_data1/dk/c",I1,"/dk",I1,".corr.",I3,"C")')
OPENW,unit,cname,/GET_LUN
bcorr = BYTE((128 * corr) + 0.5)
WRITEU,unit,bcorr

END