Traditionally, there are 5 main "Sailor Moon" series:
1. Sailor Moon (1992-1997): This is the original series, also known as "Sailor Moon R" and "Sailor Moon S."
2. Sailor Moon SuperS (1995-1996): This is a separate arc within the original series, focusing on a different antagonist and storyline.
3. Sailor Moon Stars (1996-1997): This is the final arc of the original series.
4. Sailor Moon Crystal (2014-2016): This is a more faithful anime adaptation of the manga. It covers the first three arcs (Sailor Moon, R, and S).
5. Sailor Moon Eternal (2021): This is a film adaptation that covers the "Sailor Moon SuperS" arc.
So, technically, there are 5 separate series.
However, "Sailor Moon SuperS" is often considered part of the original series rather than a separate one. So, you could argue there are only 4 series:
1. Sailor Moon
2. Sailor Moon Crystal
3. Sailor Moon Eternal
4. Sailor Moon Stars
It all comes down to how you define a "series"!