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			       CN
			NORMALISE the CCF
	 Sub to normalise a CCF by the no. of common non-zero points.
	 The MASKed file contains NN0 non-zeros, packed with zeros
	 up to NPTS - so the CCF must be divided by a factor adjusted
	 to represent the no. of common non-zeros at any given shift.
		max correlation (auto-corr) adjusted to unity.

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    SADSPT.LOG    24-OCT-81

 TYPE OPTIE                              24-OCT-1981 20:54:26.90
 >>>CN                                                                              
 OPTION CN
 OPEN FILE CONTAINING REAL DATA WITH CCF
 TYPE FILENAME (<CR> FOR DEFAULT)
 FILIR=REAL
 There are   3 maps in the file       
 Reading from the file
    3 rows of 1024 pixels in R4 format
 TYPE MAPNUMBER OF INPUT DATA
 MAPIR=3
 TYPE MAPNUMBER OF OUTPUT NORMALISED DATA
 MAPOR=4
 File extended to map   4

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