The planisphere is the perfect way to learn how to recognize stars and constellations. Every planisphere is designed for a certain latitude zone. The PLN-40 is designed for 40° north, which is good for most of North America (but also, for instance, Southern Europe, as well). The very accurate PLN-40 includes 700 stars and 300 "deep-sky" objects, some useful tips and features, Right Ascension and Declination.