All that exposition completed, you now have enough data to understand this:
Some fans of the original 1978 series decided to take all of Galactica 1980, and, from that footage and some original-series footage, put together a series finale for the original 1978 Battlestar Galactica. They also steal footage from other shows - mostly effects footage - and include new SFX of their own to have it make sense. (For example, there's a clip from Independence Day, only now, the alien raiders are original-series Cylon raiders.)
If any of this makes any sense to you at all, please enjoy:
Battlestar Galactica: The Promised Land
It's a bit slow in the middle, and a little choppy up front, but it finishes well. Unlike most of these fan-redits of incomplete series, this one has a proper ending, and the way they do it is pretty good. All ♥ to you, crazy fans! All ♥ to you and your crazy fanac.