I love astronomy very much, passion and love for astronomy came to me when I first heard from my father about solar eclipse in 1995 - ----> I love astronomy very much. My passion and love for astronomy came to me when I first heard from my father about the solar eclipse in 1995.
which made the sky was bright suddenly dark. I was curious to know why it could happened and this story urged me to learn, explore and keen on astronomy. ----> Which made the sky suddenly dark. (Was and bright is not needed in this case) I was curious to how it could happen, so this story urged me to learn, explore and heightened my interest in astronomy. (How should replace the why, so replaces and because the before statement tells us what made you more interested in astronomy).
Since then astronomy always plays a significant part in my life.---> Since then, astronomy always played a significant part in my life. (almost a perfect sentence, however play should be in past tense).
My school do not teach astronomy. But I have studied astronomy myself and this also quite same as which I study on class. --->My school doesn't teach astronomy, so I studied astronomy myself. What I self-studied were quite the same in comparison to what I studied in class. (do not sounds a little more unnatural, and replace But with so, because the above statement explains why you self-study. What you taught yourself was similar to in class so this sounded more natural.)
When I learning astronomy, such as the telescope, I can learn more about optics, or reading about stars, I will know nuclear physics more - which I were taught on class. So that I can easily understand the lesson and reach better results.--->When I'm learning about astronomy such as the telescope I can learn more about optics or reading about stars.
Astronomy helped me learn a lot of real knowledge, which is really important in my daily life.---> Astronomy helped me learn a lot which is really important in my daily life.