Was there a time in the universe when the first eclipse could be viewed?
Amazingly we may actually have a plausible answer to this question! For an eclipse to occur, you first need a star, and then a planet with a moon for which the moon will provide the eclipse. At 1 billion years after the Big Bang, the oldest known planet PSR B1620-26 b had already formed. Located in the globular cluster Messier-4 about 12,400 light-years from Earth, it bears the unofficial nicknames "Methuselah" and "The Genesis Planet" because of its extreme age: about 12.8 billion years. The planet is in orbit around the two very old stars: A dense white dwarf star and a neutron star. The planet has a mass of 2.5 times that of Jupiter, and orbits at a distance a little greater than the distance between Uranus and our own Sun. Each orbit of the planet takes about 100 years. Like the large planets in our solar system, it is not unreasonable to assume that Methuselah may also have one or more moons, and that one may provide an eclipse of the white dwarf star from the surface of Methuselah, or that from the vantage point of one of its moons, another moon may provide such an eclipse or transit!