Complex sentence: The Rapid Eye Mount Telescope (REM) is a small rapid-reaction automatic telescope with a primary mirror of 60 centimetre, in an alt-azimuth mount that started operations in October 2002.
Split into simpler sentences: The Rapid Eye Mount Telescope (REM) is a small rapid-reaction automatic telescope with a primary mirror of 60 centimetres. The telescope is in an alt-azimuth mount and started operations in October 2002.