I love the Astronomy Picture of the Day website. It is my default for having beautiful, work safe, not personal, wallpaper on my office computer.
Not every picture they post is good for wallpaper, but many are. In fact, while I try to update my wallpaper at least once a week and sometimes more, my current wallpaper is from December 13.
It’s soothing to take a moment to look at the night sky in the midst of a hectic work day, especially in the PNW, when, during the winter, we can go forever without seeing the moon and stars ourselves.