The coverage area depends on the Star Shower’s distance from the surface. Further away the projector, the larger the coverage and the bigger the stars (and more diluted). We recommend you bring the unit closer to your home, so that the lights become more concentrated to a specific area and also play with the angles until you get the right coverage, without being intrusive towards your neighbors.
Another idea is to add a black-out filter to the projector, made from simple cardboard. Just cut out the outline of where you want the stars and it’ll block the rest. Paint it flat black and use tape to attach it to the Christmas lighting projector.