$ cat pm_11149401.pl
#!env perl
use strict;
use warnings;
use Data::Dumper;

### Find the table start and column header lines

my ($dashes, @tmp);
while (<DATA>) {

  # We've found the end of the column headings when we find a line of dashes and
  # blanks with at least eight sequential dashes
  $dashes=$_, last if /^[-\s]*-{8}[-\s]+$/;

  push @tmp, $_;

  # The data we'll build the column headers / keys from is only from lines
  # immediately before the dash bar
  @tmp=(), next if /^\s*$/;
}
die "No dash bar found!" unless defined $dashes;

### Build the column descriptions

# First need the starting position and width of each column

my $col=0;
my @coldefs;
while ($dashes ne '' and $dashes =~ /^(\s*)(-*)/) {

  # skip blanks
  $col += length($1);

  if (length $2) {
    push @coldefs, { beg=>$col, len=>length($2) };
    $col += length($2);
  }

  $dashes = substr($dashes, length($1)+length($2));
}

# Build the column keys
for my $tmp (@tmp) {
  for my $ar (@coldefs) {
    my $chunk = substr($tmp, $ar->{beg}, $ar->{len});
    $chunk =~ s/(^\s+|\s+$)//g;
    $chunk =~ s/[^-a-zA-Z0-9_]+/_/g;
    $ar->{key} .= $chunk;
  }
}

# Parse the table
my @records;
while (<DATA>) {
  last if /^\s*$/;

  my $hr = {};
  for my $ar (@coldefs) {
    my $chunk = substr($_, $ar->{beg}, $ar->{len});
    $chunk =~ s/(^\s+|\s+$)//g;
    $hr->{$ar->{key}} = $chunk;
  }
  push @records, $hr;
}

print Dumper(\@records);

__DATA__
Annular-Total  Eclipse  of  2023 Apr 20 - multisite predictions

                                               1st Contact
Site               Longitude Latitude  Elvn      U.T.     PA Alt
                     o   '    o   '       m     h  m  s     o  o
-----------------  -------- --------- ------   --------   --- --
Auckland           174 45.  -36 55.       0     4 33 59   313 13
Blenheim           173 55.  -41 35.      30     4 40 34   326 11
Cape Palliser      175 25.  -41 35.       0     4 42 28   327  9
Cape Reinga        172 45.  -34 25.      50     4 30 11   307 17
Carterton          175 35.  -41  5.       0     4 40 35   324 10
Dannevirke         176  5.  -40 15.     200     4 39  9   321 10
East Cape          178 35.  -37 45.       0     4 37 58   315 10
Featherston        175 25.  -41  5.      40     4 40 36   325 10
Gisborne           178  5.  -38 45.       0     4 38 29   317 10
Great Barrier Is   175 25.  -36 15.       0     4 34 15   312 13

$ perl pm_11149401.pl
$VAR1 = [
          {
            'Elvnm' => '0',
            'lto' => '13',
            'Longitudo_' => '174 45.',
            'Site' => 'Auckland',
            '1st_ContU_T_h_m_s' => '4 33 59',
            'Latitudeo_' => '-36 55.',
            'PAo' => '313'
          },
          {
            'lto' => '11',
            'Elvnm' => '30',
            'Site' => 'Blenheim',
            'Longitudo_' => '173 55.',
            'PAo' => '326',
            'Latitudeo_' => '-41 35.',
            '1st_ContU_T_h_m_s' => '4 40 34'
          },
          {
            'Elvnm' => '0',
            'lto' => '9',
            'Site' => 'Cape Palliser',
            'Longitudo_' => '175 25.',
            '1st_ContU_T_h_m_s' => '4 42 28',
            'PAo' => '327',
            'Latitudeo_' => '-41 35.'
          },
          {
            'Site' => 'Cape Reinga',
            'Longitudo_' => '172 45.',
            'PAo' => '307',
            'Latitudeo_' => '-34 25.',
            '1st_ContU_T_h_m_s' => '4 30 11',
            'lto' => '17',
            'Elvnm' => '50'
          },
          {
            'Latitudeo_' => '-41  5.',
            'PAo' => '324',
            '1st_ContU_T_h_m_s' => '4 40 35',
            'Longitudo_' => '175 35.',
            'Site' => 'Carterton',
            'lto' => '10',
            'Elvnm' => '0'
          },
          {
            'Longitudo_' => '176  5.',
            'Site' => 'Dannevirke',
            '1st_ContU_T_h_m_s' => '4 39  9',
            'Latitudeo_' => '-40 15.',
            'PAo' => '321',
            'Elvnm' => '200',
            'lto' => '10'
          },
          {
            'Elvnm' => '0',
            'lto' => '10',
            '1st_ContU_T_h_m_s' => '4 37 58',
            'PAo' => '315',
            'Latitudeo_' => '-37 45.',
            'Longitudo_' => '178 35.',
            'Site' => 'East Cape'
          },
          {
            'Longitudo_' => '175 25.',
            'Site' => 'Featherston',
            '1st_ContU_T_h_m_s' => '4 40 36',
            'Latitudeo_' => '-41  5.',
            'PAo' => '325',
            'Elvnm' => '40',
            'lto' => '10'
          },
          {
            'lto' => '10',
            'Elvnm' => '0',
            'PAo' => '317',
            'Latitudeo_' => '-38 45.',
            '1st_ContU_T_h_m_s' => '4 38 29',
            'Site' => 'Gisborne',
            'Longitudo_' => '178  5.'
          },
          {
            'PAo' => '312',
            'Latitudeo_' => '-36 15.',
            '1st_ContU_T_h_m_s' => '4 34 15',
            'Longitudo_' => '175 25.',
            'Site' => 'Great Barrier Is',
            'lto' => '13',
            'Elvnm' => '0'
          }
        ];