Exclude Tags by Array

and thanks for any help!.

I'm trying to display all of the tags except ones that start with a token ("Author: ").

I have figured out how to exclude a single tag (just typed it into the exclude parameter).

I have figured out how to exclude an array of tags (created an array and manually added a couple of values).

But I haven't figured out how to fill the array based on get_term_by (or whether or not that is the best way to approach this).

<div id="tagarea">
<div class="contained">
  <h2>Categories</h2><br>
  <?php
    //$excludetags = array(136,135);
    $excludetags = get_term_by('name', 'Author:*','post_tag');
    $args = array(
    'separator'                 => " ... ",
    'orderby'                   => 'name',
    'order'                     => 'ASC',
    'exclude'                   => $excludetags,
    'include'                   => null,
    'topic_count_text_callback' => default_topic_count_text,
    'link'                      => 'view',
    'taxonomy'                  => 'post_tag',
    'echo'                      => true,
    'child_of'                  => null, // see Note!
     );
 ?>
<?php wp_tag_cloud( $args ); ?>
</div>

I also tried

$excludetags = array(get_term_by('name', 'Author:*','post_tag'));

but that doesn't work, either.