; PR200L Image Motion Computation using red-leak pile up
;
; list of PR200L observations 
;

	list = [8695,8698,8700,8709,8712,8716,8718,8720,8722, $
	        8724,8727,8729,8731,8733,8737,8742]
	nobs = [   2,   2,   2,   2,   3,   2,   2,   2,   2, $
	           3,   2,   2,   2,   2,   2,   2]
	
	xc = 878 & yc = 498
	n = n_elements(list)
;
; determine x profiles
;
	xprofiles = fltarr(31,n)
	for i=0,n-1 do begin
		acs_cr,indgen(nobs(i))+list(i),h,d,/disp		
		sub = d(xc-15:xc+15,yc-6:yc+6)
		tvscl,rebin(sub,310,130,/sample)
		xprofiles(*,i) = total(sub,2)
	end
;
; compute cross correlation of spectra from forth
;
	xcorr = fltarr(n)
	for i=0,n-1 do begin
		cross_correlate,xprofiles(*,4),xprofiles(*,i),off
		xcorr(i) =  off
	end
;
; Get observation times
;
	dbext,list,'expstart,exptime',start,integ
	time = start + integ/60.0d0/60.0d0/24.0d0/2.0
	time = (time - time(0))*24
;
; fit by straight lines (ignore first three points, profile too weak)
;
	c = poly_fit(time(3:*),xcorr(3:*),1,fit)
;
; Plot results
;
	set_plot,'ps'
	device,/land,file='PR200L_x_motion.ps'
	set_xy,2,6
	!y.style=0
	!p.thick=3
	!x.thick=3
	!y.thick=3
	!p.font=0
	!p.title='PR200L Image Motion'
	!x.title='Time Since First Observation (Hours)'
	!y.title='X - Image Motion (pixels)'
	plot,time(3:*),xcorr(3:*),psym=4,symsize=2,xstyle=1
	oplot,time(3:*),fit
	device,/close	
	print,c
;       1.7664730
;     -0.58717962
nd