I was really impressed after watching this video. I realzed how I am blesssed.
In English, Shingetsu means new moon. So I think the reason why the author used this term is that we have to think about not only the things we can see but also we can not see because Shingetsu is impossible to see. I don't know what the author really wanted to tell us and the answer, but I came to think and thank to what I can not see in my eyes.