eval {
                require Physics::Solar::VSO::Config;
        };
        if ($@) {
                die "Physics::Solar::VSO::Config not installed";
        }
        Physics::Solar::VSO::Config::AddVariable (
                'REG_DIR',
                desc    => 'location of the registry data.  Will be guessed if left undefined',
                default => undef,
                module  => 'registry',
        );
        Physics::Solar::VSO::Config::AddVariable (
                'REG_DUMP',
                desc    => 'location to store pre-parsed registry data, if defined',
                default => undef,
                module  => 'registry',
        );