Supposedly there are hundreds of billions of galaxies. They write this as if these very old stars are very rare, but maybe all the other galaxies have some, not just our galaxy.
Astronomers counted the galaxies in a small portion of the sky and multiplied by the balance of the sky.
The portion was about one-tenth the apparent diameter of the moon--about what you would see by looking through a drinking straw, or a twenty-six millionth of the whole sky. They found 10,000 galaxies: