Thanks for the tips, Karl. I actually wasn't as concerned about Google rankings, though I did do a quick search just now and I'm ranked 17th if you do a search for "astronomy podcast" in Google (even on a separate browser where I'm not logged in).
I'm more concerned at the moment about iTunes not showing it in searches. If I search just for podcasts with the name "astronomy" in the title, it doesn't show. If I search for "astronomy" in the description, it doesn't show. I checked my RSS feed and it seems everything's in order and I'm not missing anything, but I can't figure out why it's not showing.
Here's part of my feed code:
<?xml version="1.0" encoding="UTF-8"?>
<rss xmlns:itunes="http://www.itunes.com/dtds/podcast-1.0.dtd" version="2.0">
<channel>
<title>Exposing PseudoAstronomy</title>
<link>http://podcast.sjrdesign.net</link>
<language>en-us</language>
<copyright>℗ & © 2011 Stuart Robbins</copyright>
<itunes:subtitle></itunes:subtitle>
<itunes:author>Stuart Robbins</itunes:author>
<itunes:summary>Listen to learn the real state of science behind astronomy-, physics-, and geology-related creationist claims, hoaxes, conspiracy theories, misconceptions, and bad or incomplete media reporting.</itunes:summary>
<description>Listen to learn the real state of science behind astronomy-, physics-, and geology-related creationist claims, hoaxes, conspiracy theories, misconceptions, and bad or incomplete media reporting.</description>
<itunes:owner>
<itunes:name>Stuart Robbins</itunes:name>
<itunes:email>feedback@sjrdesign.net</itunes:email>
</itunes:owner>
<itunes:image href="http://podcast.sjrdesign.net/images/logo_med.jpg" />
<itunes:category text="Science & Medicine">
<itunes:category text="Natural Sciences"/>
</itunes:category>
<item>
<title>Episode 37: Space Law and Extraterrestrial Property Rights, Interview with Nigel and Lady Saint Whitehall</title>
<itunes:author>Stuart Robbins</itunes:author>
<itunes:subtitle>Interview with two lawyers about space law and owning rights to property and materials off-Earth.</itunes:subtitle>
<description>I interview Lord and Lady Saint Whitehall, two lawyers with pseudonyms, as a follow-up to Episode 27 (Stellar Scams). We discuss the Outer Space Treaty, legal precedents in the relevant areas, and extrapolate to what may need to happen legal-framework-wise in the future as private companies start to exploit extraterrestrial resources.</description>
<itunes:summary>I interview Lord and Lady Saint Whitehall, two lawyers with pseudonyms, as a follow-up to Episode 27 (Stellar Scams). We discuss the Outer Space Treaty, legal precedents in the relevant areas, and extrapolate to what may need to happen legal-framework-wise in the future as private companies start to exploit extraterrestrial resources.</itunes:summary>
<itunes:image href="http://podcast.sjrdesign.net/images/logo_med.jpg" />
<itunes:explicit>no</itunes:explicit>
<enclosure url="http://podcast.sjrdesign.net/media/podcasts/PseudoAstro_037.mp3" length="29725398" type="audio/mpeg" />
<guid>http://podcast.sjrdesign.net/media/podcasts/PseudoAstro_037.mp3</guid>
<pubDate>Thu, 24 May 2012 12:00:00 GMT</pubDate>
<itunes:duration>49:36</itunes:duration>
<itunes:keywords>astronomy, pseudoscience, scams, space law, moon</itunes:keywords>
</item>
...
</channel>
</rss>