#!/usr/bin/perl
use warnings;
use strict;
use PDL;
use PDL::Graphics::PGPLOT;

my $a = rfits "m51_raw.fits";
my $flat = rfits "m51_flatfield.fits";
imag $flat;
<>;

my $gal = $a / $flat;

# !!!!!!!!!   this is line 18  !!!!!!!!!!!!!!!!!!!!!!
my $section =  $gal(337:357, 178:198 );

 imag $section; # It's the bright star
<>;
__END__