My favourite constellation is Andromeda. It is one of the fairest, and I think part of its beauty consist in the difficulty to find it. The joy perceived when finally you can distinguish it in the night add something to the the pleasure of contemplating its appearance.
Also, additional charm is added by the fact that it contains the farthest object we can observe without telescope, the Andromeda galaxy.
Andromeda was already known in the ancient time: Tolomeo described it in its work, in the II century b.C., and its myth was pretty famous: Eschilo and Sofocle, two of the greatest greek tragedians, wrote a play on it and Ovidio wrote about it in the Metamorphoses. Andromeda was the daugher of the king of Ethiopia, Cefeo, and her mother Cassiopea made the mistake of brag about her beauty: she said that she and her daughter were as beautiful as, if not even more, the Nereids. They did not take this as a compliment, and felt insulted asked to their protector, the god of the sea Poseidon, to defend their supremacy.
Poseidon decided to act upon their request, and summoned a monster to attack the cost of Ethiopia. As the situation was worsening for his country, the king asked to the oracle how to mend their mistake. The only way was to sacrifice the virginal daughter to a sea monster. Andromeda was then chained to a rock in front of the sea, awaiting her fate, when Perseo, the hero killer of the Medusa, happened to pass by.
Perseo immediately fell in love for the shy Andromeda and save her after being granted the permission of marriage from the father, killing the approaching sea monster. According to Ovidio the father had second thoughts, and Athena (the goddess of Wisdom) had to intervene to grant their marriage and promised them to become part of the sky. In fact, Beside Andromeda there are the constellation of Perseo and Cassiopea.
This is what tradition reported about Andromeda history. But I imagined things going in another directions.
Andromeda was a very shy, honest girl, but strong in her principles. She did not share the mother's vanity, always considering her thoughts more important than her face. She felt the responsibility of being the king's daughter, and she understood that being a princess meant above all do the right thing for its people.
When Cefeo went to ask how to remedy the situation, Poseidon gave him only one option: an hero had to kill the sea monster to appease his ire, or otherwise Ethiopia would have been slowly destroyed.
Cefeo did not have sons, therefore he opened a contest into his kingdom to find the right person for the job.
The winner of the contest would have to risk his life but, if succeeded, he would have gained also Andromeda as his wife. When Andromeda heard the terms of the contest and that she became a prize, she indignantly spoke with the father: "Am I nothing more than a trophy for you, father, that I am to be a prize like an object?" She was ready to sacrifice her future for the wellbeing of her people, but she was not prepared to be treated like a thing. The king replied sadly: "You are more than that, my beloved daughter, but you need to understand that no man would risk his life without a worthwhile promise". Andromeda, willing to affirm her value as woman and as human being, proposed to the father to fight herself for her life and the future of the country. Cefeo did not agree at the beginning, but Cassiopea intervened: "Let her fight for her life, as a marriage without love is a fate worst than death". Was then decided to let Andromeda fight, and to fool the seamonster she acted as she was chained to the rock. When it approached to a sword distances, Andromeda took off the chains and used them to blind it. Mad with pain but now blind, the beast moved toward the rocks where Andromeda was, but she quickly moved and the monster smashed its head against the cliff.
For the smart method used by Andromeda in the fight, Athena rewarded her with the promise of be part of the sky to remember every woman to be the creator of her own fate.