Simplify the following text for a Grade 10 native English-speaking person.
Original: Rainbow ( also known as Ritchie Blackmore 's Rainbow or Blackmore 's Rainbow ) were an English rock band , controlled by former Deep Purple guitarist Ritchie Blackmore from 1975 to 1984 and 1994 to 1997 .
Simplified: Rainbow ( also known as Ritchie Blackmore 's Rainbow or Blackmore 's Rainbow ) were an English hard rock band , controlled by guitarist Ritchie Blackmore from 1975 to 1984 and 1994 to 1997 .