sub func {
my ($event, @planet_names) = @_; # read in parameters supplied by caller as in func($xyz)
# check that we have some names and that event contains the fields we need
# return undef on error.
# caller must check if received undef!
return undef unless @planet_names;
return undef unless exists $event->{epoch};
...
my %returned_planets = ();
for my $a_planet_name (@planet_names){
my $planet = Astro::Coords->new( planet => $name );
...
$returned_planets{$a_planet_name} = $planet;
}
# return to the caller results as a hashref
# I always use refs for params and results. others may not.
return \%returned_planets;
} # end of my function

# example use
my $ret = func($anevent, "venus", "saturn");
die "func() failed" unless defined $ret;
# and now do what you like with the results.

##</code><code>##

for my $event (@events) {
  my $epoch = parse_event($event);

  my ( $MoonPhase, $MoonIllum, $MoonAge, $MoonDist, $MoonAng, $SunDist,
    $SunAng ) = phase($epoch);