If you are a mobile user, Google’s "Sky Map" is a fantastic, free alternative. It is an open-source planetarium app for your phone. You simply point your phone at the sky, and it identifies stars, constellations, and planets in real-time.
The defining feature of the "Pro" variant was the size of its database. While basic free apps might show you a few thousand stars and the Messier catalog (110 objects), Skymap Pro 12 comes pre-loaded with a database of over and 13 million deep sky objects (galaxies, nebulae, and star clusters). skymap pro 12 free
Detailed deep-sky object databases including NGC, IC, and Messier catalogs. If you are a mobile user, Google’s "Sky