The Vatican did not name a telescope “Lucifer.” The Vatican Observatory shares space (no pun intended) with other organizations and groups. The Vatican Observatory does not own each piece of equipment, nor can it give official names or nicknames to things it does not own. Another group installed a telescope it nicknamed Lucifer.
Its a telescope built by the Max Planck Institute for extraterrestrial physics, and according to the Planck Institute website, it stands for LBT Near Infrared Spectroscopic Utility with Camera and Integral Field Unit for Extragalactic Research. It is noted on the website that its official abbreviation has been changed to LUCI.