Possible Clues:

• Voyager 2 flew by it
• Triton's planet
• It was first observed in 1846
• Writer upset over air from one with several satellites
• Sea god; planet
• New record with piece of music, extract from The Planets
• Writer returns with melody for one of 'The Planets'
• Write (reversed) + Ditty = Sea god
• Write up a song of the sea for god
• Writer upset English teachers over revolutionary body