The easy way to identify stars! Simply compare the stars you can see in the sky through one eye with the annotated and illuminated map you view inside star pocket through the other eye. 70 constellations and 1, 500 stars demystified. All you have to do beforehand is set the time and date on the rings outside, and align it in the right direction using the built-in compass. Latitude compensation rings and Star maps for both hemispheres are included, so you can use it anywhere in the world. 15 cm long, with the water-resistant bag.