This is quite gorgeous. The texture of the string swells, rhythmic piano swells, and plucky melody absolutely give the sense of arches in the sky with rain, and the harmony is so colorful, making this a beautiful representation of a rainbow. I appreciate the subtle use of snare, triangle, and other subtle percussion instruments to add some sparkle. If this is your first orchestral piece, then cannot wait to hear music you come up with in the future! Great work on this and thank you for sharing!