[aerohead]

In # 97 (permalink ) freebeard shared that, it is from the Bible that the mention of our Sun going dark was mentioned.
I have three different Bibles, have read all three, and off the top of my head, have no recollection of reading such a thing.
A total solar eclipse would explain a short-term event.
Anything longer would require a larger body, beyond the orbit of the Moon, transiting the Sun, and by doing so, occulting the Sun, however, it would require a very slow relative motion, as witnessed from Earth, to explain a longer duration of darkness. 100-days seems like unicorn horns.
Atmospheric scintillation causes stars to 'wink' all the time when thermal convective currents are present in the night sky. Absorbed heat in a telescope tube itself can create challenges for 'seeing', until the telescope achieves equilibrium temperature.
The odds that any star, other than a cepheid variable could vary in luminosity for 100-days is problematic.
Once daylight comes, any star observation comes to an end. If a variable like Mira was dimmed, you would see it at all, even under magnification, until it's cycle brought it back around.
How one would be able to account for any specific star without charts, and not mistaking one for another would be an enormous challenge in ancient times.