The moon does not turn the color of blood, at least not fresh blood. It turns more the color of blood that you have gotten on a white towel when you cut yourself shaving and then tried to bleach out of it. But if you called it the Color of Bleached-Out Blood on the Guest Towel You Now Have to Hide from Your Wife Moon, nobody would buy your book about it.
Likewise, if you called it The Wet Leaf Moon, The Rusty Spot on the Toilet Moon or the The Color of That Old T-Shirt That Used to be Red Moon, shades that the moon actually turns to during a lunar eclipse, people would just think you were peculiar.
So if you're like the Reverend Mark Blitz you call it the Blood Moon and write a book about it (and also publish a calendar and a DVD and make all three available for one low price of $43.34) claiming that it portends the end of the world and the return of Jesus. People who are looking forward to the end of the world and the return of Jesus, mostly because they confidently expect that He will consign all of their neighbors that they don't like to Hell, will buy this book. You will get rich, especially if you double down by claiming that these Blood Moons are unique because they all fall on Jewish holidays. You can also say it is ominous that all of your Blood Moons will be visible from the United States because, while the Bible mentions the US exactly zero times, most of your prospective readers live in the United States, within ten miles of a Wal-Mart, which is where most of your books will be sold.
If you point out that all lunar eclipses occur on full moons, and that the timing of all Jewish holidays is based upon full moons and that your Blood Moon falling on a Jewish holiday is not a portent but an inevitable coincidence, your sales will plummet. If you want to see them vanish into nothing, you might mention that lunar eclipses are visible to everybody on the night side of Earth, so the odds of any one being visible from the US is a less-than-scant 50/50.
But if you really want people to ignore you, you could make an end of the world prediction like my own, which is that when the human race finally gets hit with that cosmic pie in the face, Jesus will have nothing to do with it. If a comet is on course to crush us, astronomers will not see Jesus skateboarding on its tail as it comes sailing across the sky. If the Earth's magnetic field reverses, the Son of God will not appear in glory holding a compass upside-down and grinning sardonically; if robots take over the Earth, the head Terminator will not wear a robe and sandals.
So my wallet will continue to be empty while Reverend Blitz's swells with the dollars of those who happily look forward to all of humankind being turned into smutz. But I don't resent the guy. In fact, I'm grateful to him. Usually I miss lunar eclipses. I read that one is coming up, but then I forget about it until I realize that it's already passed. Thanks to the Blood Moon being on the front page of every Internet portal, this time I remembered to watch.
Thanks, Reverend. Don't expect me to buy the book, though.