;
; linearity test for NAC camera
;

fnames=['atest.1.fit','atest.2.fit','atest.3.fit','atest.4.fit','atest.5.fit',$
'atest.6.fit','atest.7.fit','atest.8.fit','atest.9.fit','atest.10.fit']

exposuretimes=[10,20,30,40,50,60,70,80,90,100]

img_mean=fltarr(10)
 
for i=0,9 do begin
 img=swap_endian(rfits(fnames(i)))
 img_mean(i)=mean(img)
endfor

c=poly_fit(exposuretimes(0:2),img_mean(0:2),1)
linearfit=poly(exposuretimes,c)

set_plot,'ps'
device,/encapsulated,filename='atest_1.ps'
plot,exposuretimes,img_mean,psym=2,xtit='Exposure [sec]',ytit='Mean [ADU]',$
     tit='Linearity test',chars=1.6,yran=[0,1.5e4],ystyl=1
oplot,exposuretimes,linearfit,linestyl=2
device,/close
set_plot,'x'

nonlin=(-1.*linearfit+img_mean)/(linearfit)

set_plot,'ps'
device,/encapsulated,filename='atest_2.ps'
plot,img_mean/1000.,nonlin,psym=2,xtit='Mean [10!U3!NAUD]',$
     ytit='Fractional Deviation',$
     tit='Linearity Deviation',chars=1.6,tic=1
device,/close
set_plot,'x'


the_end:
end