How are the constellations important in the novel, Lost Roses?

The constellations represent Luba's passion for astronomy, her love for Sofya, navigation, and herself and Sofya's mother. Luba is intensely interested in the night sky, and as a young teenager, knows more about astronomy than most adults. After the death of her mother, Sofya and Eliza take Luba to the Paris Planetarium and Sofya tells her sister that their mother now lives in the stars. While staying at the estate in Malinov, Luba constructs a constellation map on Sofya's ceiling, with groups of stars representing the astrological signs of Sofya and Afon. Upon breaking out of confinement on the estate and escaping the rebels, Luba finds her way to Sofya in Paris by navigating using the stars.