Sailor Moon Mythology: Altair and Vega, or The Weaver Girl and the Cowherd
The Weaver Girl and the Cowherd is an ancient Chinese folktale that dates back to over 2600 years ago. It is about the love story between Zhinü (the weaver girl, symbolizing the star Vega) and Niulang (the cowherd, symbolizing the star Altair). Their love was not allowed, thus they were banished to opposite sides of the Silver River (symbolizing the Milky Way). Once a year, on the 7th day of the 7th lunar month, a flock of magpies would form a bridge to reunite the lovers for one day. The tale is celebrated in the Japanese festival of Tanabata, which is usually celebrated between July and August. (via Wikipedia)
In Sailor Moon
The Tanabata festival as well as the tale that inspired it feature prominently in the side story Chibiusa’s Picture Diary 2, which is entitled “Beware the Tanabata!” The legend (as well as its basis in astronomy) is explained in detail by Ami and Rei:
Anyway, Chibiusa is given a Sailor Moon watch by Mamoru for her birthday; she soon discovers that many other girls bought watches themselves. Soon afterward, on July 7th, all of the girls (including Chibiusa) who got watches are called to a park, although Diana manages to snap Chibiusa out of it. Once they reach the park, they see the mysterious vendor who sold the watches trying to persuade the crowd of girls that they don’t need men and should cast them out of their lives. Chibiusa transforms and protests that men and women need to live together, not apart. The speaker then “reveals” herself to be “Sailor Moon” - though she is actually an impostor.
Chibiusa quickly reveals the deception and discovers that the figure is actually Vega. Vega tells Chibiusa that she is fat and plain, causing her husband to no longer desire her. After he saw he without her makeup, she says, it has always rained on July 7th, making her feel that he is avoiding her.
Her two companions feed into her despair and reveal their plot to steal the energy of both the girls and Vega.
Diana realizes that they are Epsilon and Zeta, the other two Weaver stars that Ami mentioned. Chibiusa attacks them with Pink Sugar Heart Attack, destroying them and setting the girls free. Altair then appears and reassures his wife of his love for her, stating that he will never leave her for another girl. Chibiusa expresses hopeful wishes for the pair in her diary.