This is the Daedalus class, pre-TOS explorer, USS Horizon, NCC-176. The Horizon is notable for the accidental contamination of the civilization on Sigma Iotia II when a book on the Chicago gangs of the 1920s was accidentally left behind by the departing starship.
This is my first addon and is far from perfect. Improvements and "fixes" will follow as my skills improve. Constructive criticsm and advice are welcome and humbly appreciated.