From Misty Rain Scans:

Due to the nature of her father's job, Hinoka has transferred schools several times. When her friends from her first school ceased contact after her transfer, Hinoka resolved never to become close to anyone again. Now in her seventh transfer school, she joins the idle astronomy club, thinking she could continue living her life alone. But what happens when she meets a boy who shines like the brightest star, Sirius, on a cloudy day?