This add-on places the Borg and the Voyager in orbit around the star Vega. Once there, you can use Celestia's built-in Solar System Browser under the Navigation menu to locate various objects. The Enterprises are located in orbit around the Earth, and the Deep Space 9 objects are located in orbit around the star Alsafi.
Updated in 2022 to added updated atmospheres to improve the planets looks due to addon age and replaced Vega 1's texture with a unique textures as opposed to reusing the Neptune texture.
How to install add-ons? Find out here.