This system could potentially be used with the Community Ocean Project’s skydome, however it’s not something I’ve actively tested nor would it be something I’d be able to immediately offer support for. Orbit is designed to be an all-in-one inclusive system, though the amount of customization in place could make interaction with other systems possible with some decent understanding of blueprints.
As far as the day/night cycle goes, there currently isn’t a standardized set of metrics for exact latitude, longitude, or UTC offsets. There is an option to use your local time at runtime by grabbing your computer system’s time, but the day/night functionality is more tiered toward the most basic passage of time simulation, rather than a scientifically accurate simulation.
Please let me know if you have any questions, I’d like to help you make the most informed decision possible prior to you deciding whether or not to buy Orbit 
Cheers!