Yeah, basically you just need the name to summon. Magic will then take the name and and query the Top Level Netherworlds Servers (they are run by TCANP: Theran Corporation for Assigned Names and Patterns) for the actual physical location of the Horror and then establish a connection.
Due to the way Astral Space works, all magicians are told to never attempt to cast several spells at the same time (known as Multicast) as this can overwhelm Astral Space and result into a Broadcast storm (also known as a 'Scourge') that can have lasting repercussions on the ability of Astral Space to serve as a conduit to magic.
