diff -u -r nomv1.04.0/tam/fits/Fits.java nom/tam/fits/Fits.java
--- nomv1.04.0/tam/fits/Fits.java	2009-12-24 09:10:30.000000000 +0100
+++ nom/tam/fits/Fits.java	2010-06-22 16:54:43.742940361 +0200
@@ -1044,4 +1044,125 @@
 	String resul = new String(asc,15,1) ;
 	return resul.concat(new String(asc,0,15)) ;
     }
+
+	/** Create a copy of the current FITS data and return it.
+	* @since 2010-01-31
+	* @author Richard J. Mathar
+	*/
+	public Fits clone() throws CloneNotSupportedException
+	{
+		Fits s  = new Fits() ;
+		for( int h = 0 ; h < getNumberOfHDUs() ; h++)
+		{
+			try
+			{
+				/* try to preserve the order. Alternative: s.addHDU(getHDU(h)) ;
+				*/
+				s.insertHDU(getHDU(h),h) ;
+			}
+			catch ( Exception e)
+			{
+				throw new CloneNotSupportedException(e.toString() ) ;
+			}
+
+			/* Note that this is not a faithful copy, since the primary header
+			* will for example be commented with the current date of creation, and
+			* the comment within header cards may be modified relative to the original
+			* In that sense, it is mandatory to re-calculate the DATASUM and CHECKSUM keywords
+			* in the copy if they exist.
+			*/
+			try
+			{
+				BasicHDU hdu = s.getHDU(h) ;
+				Header hdr = hdu.getHeader() ;
+				if ( hdr.findCard("DATASUM") != null)
+					s.setDatasum(hdu) ;
+				if ( hdr.findCard("CHECKSUM") != null)
+					s.setChecksum(hdu) ;
+			}
+			catch( Exception e)
+			{
+				System.err.println(e.toString() ) ;
+			}
+		}
+
+		return s ;
+	}
+
+	/** Update the DATASUM and CHECKSUM keywords if present.
+	* The difference to the setDataSum() and setCheckSum() functions is
+	* that the card files are only updated if they exist.
+	* @param hdu The HDU to be updated.
+	* @see <a href="http://fits.gsfc.nasa.gov/registry/checksum.html">FITS checksum convention</a>
+	* @since 2010-02-01
+	* @author Richard J. Mathar
+	*/
+	public void updateCDsum(BasicHDU hdu)
+	{
+		Header hdr = hdu.getHeader() ;
+		try 
+		{
+			if ( hdr.findCard("DATASUM") != null)
+				setDatasum(hdu) ;
+			if ( hdr.findCard("CHECKSUM") != null)
+				setChecksum(hdu) ;
+		}
+		catch (Exception e)
+		{
+			System.err.println(e.toString() ) ;
+		}
+	}
+
+	/** Add or update the DATASUM keyword.
+	* The implementation parallels the CHECKSUM case, but needs less caution
+	* because the header card is not part of the data sum to be calculated.
+	* @param hdr the primary or other header to get the current DATE
+	* @throws nom.tam.fits.HeaderCardException
+	* @author Richard J. Mathar
+	* @see <a href="http://fits.gsfc.nasa.gov/registry/checksum.html">FITS checksum convention</a>
+	* @since 2010-02-01
+	* @author Richard J. Mathar
+	*/
+	public static void setDatasum(BasicHDU hdu)
+		throws nom.tam.fits.HeaderCardException, nom.tam.fits.FitsException, java.io.IOException
+	{
+		/* the next line with the delete is needed to avoid some unexpected
+		*  problems with non.tam.fits.Header.checkCard() which otherwise says
+		*  it expected PCOUNT and found DATE.
+		*/
+		Header hdr = hdu.getHeader() ;
+		hdr.deleteKey("DATASUM") ;
+
+		/* Convert the sequence of 2880 byte data cards into a byte array.
+		*/
+		ByteArrayOutputStream hduByteImage = new ByteArrayOutputStream() ;
+		final Data dats = hdu.getData() ;
+		BufferedDataOutputStream b = new BufferedDataOutputStream(hduByteImage) ;
+		dats.write(b) ;
+		/* Ensure that checksum() will have all the data, even those at the end of the stream
+		*/
+		b.flush() ;
+
+		/* Write the number to the DATASUM.
+		*/
+		final byte[] data = hduByteImage.toByteArray() ;
+		final long csu = checksum(data) ;
+		final String doneAt = "as of " + FitsDate.getFitsDateString() ;
+		hdr.addValue("DATASUM", ""+csu, doneAt ) ;
+	}
+
+	/** Add or Modify the DATASUM keyword in all headers.
+	* @throws nom.tam.fits.HeaderCardException
+	* @throws nom.tam.fits.FitsException
+	* @author Richard J. Mathar
+	* @see <a href="http://fits.gsfc.nasa.gov/registry/checksum.html">FITS checksum convention</a>
+	* @since 2010-02-01
+	* @author Richard J. Mathar
+	*/
+	public void setDatasum()
+		throws nom.tam.fits.HeaderCardException, nom.tam.fits.FitsException, java.io.IOException
+	{
+		for (int i=0; i< getNumberOfHDUs(); i ++)
+			setDatasum(getHDU(i)) ;
+	}
 }
diff -u -r nomv1.04.0/tam/fits/test/BinaryTableTester.java nom/tam/fits/test/BinaryTableTester.java
--- nomv1.04.0/tam/fits/test/BinaryTableTester.java	2009-07-27 08:57:02.000000000 +0200
+++ nom/tam/fits/test/BinaryTableTester.java	2010-06-22 16:29:59.677208275 +0200
@@ -9,6 +9,7 @@
 import static org.junit.Assert.assertEquals;
 import junit.framework.JUnit4TestAdapter;
 import java.lang.reflect.*;
+import java.lang.annotation.*;
 
 /** This class tests the binary table classes for
  *  the Java FITS library, notably BinaryTableHDU,