This was shared at a local email posting group I belong to and I want to share it here. Rob Ratkowski who lives in Hawaii and is a member of my local club shared this article and picture over at Earth Science Picture of the Day. Rob uses it to explain why observatories are built high on mountain top locations, and it shows why transparency is so important. Please take a moment to take a look and read.
Here's the picture, but don't forget to go and read Rob's article for his explanation, it is tremendous!