I know this is no help but, The background seems 
to be from episode 92 A pretty Boy?? The secret 
of Tenou Haruka when Usagi and Minako Chase the 
Monster of the day after he stole the pure 
crystal heart of the victim of the day.  The 
actual Cel of Sailor Moon I'am not sure I 
rewatched the episode but couldn't find that 
actual moment that Cel appeared. 

Regardless it's a beautiful cel and I wish you 
joy of it.  

Maribel, who will one day create her own Sailor 
Moon webpage so people can see her cel's.