Scheduling duplication of two tables across instances
As long as all the changes happen only on your first instance, transactional replication is what you are looking for. It was designed for this purpose and usually operates close to realtime.

You can find an introduction to replication here: http://www.sqlservercentral.com/stairway/72401/

If you need to be able to apply changes on both machines, merge replication might be the better option, but is was not designed for realtime operations. The above link has an introduction to merge replication too.