I noticed that my current solution for Google Analytics tracking using iframes wasn’t working.   The solution was to edit the tracking code on the main website, Clear Sky Tonight, to also include a reference to the second domain name.  Here is the code example that helped fix the issue.

ga(‘create’, ‘UA-XXXXXXX-Y’, ‘auto’, {‘allowLinker’: true});
ga(‘require’, ‘linker’);
ga(‘linker:autoLink’, [‘example-2.com’] );