procedure tshifts (refImage,sample1,sample2)

string refImage		{prompt="Reference image (**full name**)"}
string sample1		{prompt="Sample image 1 (**full name**)"}
string sample2		{prompt="Sample image 1 (**full name**)"}

begin

	# Variable Declarations:


	# Cleaning-up:
	delete (files="temp_*.out",go_ahea+,ver-)


	if (! defpac ("images")) {
		print("Package IMAGES needs to be loaded.")
		bye
	}
	if (! defpac ("proto")) {
		print("Package PROTO needs to be loaded.")
		bye
	}




	print (" ")
	print ("Obtaining coordinates of comparison stars ...")



	# 1. Taking coordinates from reference image:
	display (image=refImage,frame=1,erase+,bord-, sele+,repe-,fill-,zscal+,ztrans="linear", >> "temp_junk.out")
	print (" ")
	print (" *** REFERENCE IMAGE: Currently displayed in 'Ximtool' ***")
	print ("         *** Select a sample of comparison stars ***")
	print (" ")
	print ("  --> Use <a> to select each star and type <q> when done.")
	imexam(input=refImage,frame=1,image=refImage,keeplog-,defkey="a",autor+, allfram+,nfram=0,graphcu="",imagecu="",wcs="logical",graphic="stdgraph", display="display(image='$1',frame=$2)",use_dis+,flpar-, >> "temp_imexamREF.out")
	fields (files="temp_imexamREF.out",fields="1,2",lines="1-9999",quit_if-, print_f-,flpar-, >> "temp_REF.out")

	fields (files="temp_imexamREF.out",fields="11",lines="1-9999",quit_if-, print_f-,flpar-, >> "tshifts.FWHM")


	print (" ")
	print ("   List of star coordinates:")
	type temp_REF.out




	# 2. Taking coordinates from sample image 1:
	display (image=sample1,frame=2,erase+,bord-, sele+,repe-,fill-,zscal+,ztrans="linear", >> "temp_junk.out")
	print (" ")
	print (" *** SAMPLE IMAGE 1: Currently displayed in 'Ximtool' ***")
	print ("            *** Select *same* sample of stars ***")
	print (" ")
	print ("  --> Use <a> to select each star and type <q> when done.")
	imexam(input=sample1,frame=2,image=sample1,keeplog-,defkey="a",autor+, allfram+,nfram=0,graphcu="",imagecu="",wcs="logical",graphic="stdgraph", display="display(image='$1',frame=$2)",use_dis+,flpar-, >> "temp_imexamSA1.out")
	fields (files="temp_imexamSA1.out",fields="1,2",lines="1-9999",quit_if-, print_f-,flpar-, >> "temp_SA1.out")

	fields (files="temp_imexamSA1.out",fields="11",lines="1-9999",quit_if-, print_f-,flpar-, >> "tshifts.FWHM")




	# 3. Taking coordinates from sample image 2:
	display (image=sample2,frame=3,erase+,bord-, sele+,repe-,fill-,zscal+,ztrans="linear", >> "temp_junk.out")
	print (" ")
	print (" *** SAMPLE IMAGE 2: Currently displayed in 'Ximtool' ***")
	print ("            *** Select *same* sample of stars ***")
	print (" ")
	print ("  --> Use <a> to select each star and type <q> when done.")
	imexam(input=sample2,frame=3,image=sample2,keeplog-,defkey="a",autor+, allfram+,nfram=0,graphcu="",imagecu="",wcs="logical",graphic="stdgraph", display="display(image='$1',frame=$2)",use_dis+,flpar-, >> "temp_imexamSA2.out")
	fields (files="temp_imexamSA2.out",fields="1,2",lines="1-9999",quit_if-, print_f-,flpar-, >> "temp_SA2.out")

	fields (files="temp_imexamSA2.out",fields="11",lines="1-9999",quit_if-, print_f-,flpar-, >> "tshifts.FWHM")




	# Joining coordinate lists side-by-side in the one file:
	joinlines(list1="temp_REF.out,temp_SA1.out,temp_SA2.out", list2="",output="temp_coords.out",delim="",missing="Missing",maxchar=300, shortes+,verb+,flpar-)
	print (" ")
	print ("- - - - - - - - - - - - - - - - - - - - - - - - - -")
	print (" Xoffset  Yoffset        (REF - SAMPLE 1) ")
	!awk '{print ($1-$3)"  "($2-$4)}' temp_coords.out

	print ("- - - - - - - - - - - - - - - - - - - - - - - - - -")
	print (" Xoffset  Yoffset        (REF - SAMPLE 2) ")
	!awk '{print ($1-$5)"  "($2-$6)}' temp_coords.out

	print ("- - - - - - - - - - - - - - - - - - - - - - - - - -")
	print (" ")
	print (" Done.")
	print (" ")


	# Cleaning-up:
	delete (files="temp_*.out",go_ahea+,ver-)

end