pro	regis,image_list,shiftfile,x0=x0,y0=y0,xsize=xsize,ysize=ysize,$
	chain=chain,fine=fine
	cc=0.0
;	read the image list here
	files=file_list(image_list,nnn)

;	read the first image, put in the reference buff
	fxread,files(0),ref,header
	print,'Reference image...',files(0)
        ref_fn=files(0)
	openw,8,shiftfile

;	find the indices of the subarray used for correlation calculation
	if (not keyword_set(x0)) then x0=128
	if (not keyword_set(y0)) then y0=128
	x0=fix(x0)
	y0=fix(y0)
	if (not keyword_set(xsize)) then begin
	  xsize=256
	endif else begin
	  xsize=fix(xsize)
	endelse
	if (not keyword_set(ysize)) then begin
	  ysize=256
	endif else begin
	  ysize=fix(ysize)
	endelse
	x1=fix(x0+xsize-1)
	y1=fix(y0+ysize-1)

for k=1,nnn-1 do begin
fxread,files(k),data2,header
if( not keyword_set(fine)) then begin
	regis_core,ref,data2,out,[x0,x1],[y0,y1],nx,ny,cc,/nofine
endif else begin
	regis_core,ref,data2,out,[x0,x1],[y0,y1],nx,ny,cc
endelse
out_fn='scra:[echols]Rf_'+files(k)
writefits,out_fn,out,header
printf,8,ref_fn,'  ',files(k),'  ',nx,ny,cc
if( keyword_set(chain)) then begin
	ref_fn=files(k)
	ref=out
endif 
endfor
close,8
return
end