; Routine to find image motion versus time for PR130L observations
; using red leak pile-up
;
; list of PR130L observations with approximate centers
;
	list = 8800+[62,63,64,65,66,67,71]		

	xc = 302 & yc = 548
	n = n_elements(list)
;
; determine x profiles
;
	xprofiles = fltarr(31,n)
	for i=0,n-1 do begin
		acs_read,list(i),h,d
		sub = d(xc-15:xc+15,yc-6:yc+6)
		tvscl,rebin(sub,310,130,/sample)<100
		xprofiles(*,i) = total(sub,2)
	end

;
; compute cross correlation of spectra from first
;
	xcorr = fltarr(n)
	for i=0,n-1 do begin
		cross_correlate,xprofiles(*,0),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
;
; fit by straight lines
;
	time = (time - time(0))*24
	c = poly_fit(time,xcorr,1,fit)
;
; Plot results
;
	set_plot,'ps'
	device,/land,file='PR130L_x_motion.ps'
	set_xy,-0.5,2.0
	!p.thick=3
	!x.thick=3
	!y.thick=3
	!p.font=0
	!p.title='PR130L Image Motion'
	!x.title='Time Since First Observation (Hours)'
	!y.title='X - Image Motion (pixels)'
	plot,time,xcorr,psym=4,symsize=2
	oplot,time,fit
	device,/close	
	print,c
;      0.17524348
;     -0.49709936
end