The best replacement for stellarium is celestia.

The best alternatives to stellarium are rated as following:
★★★★★  celestia
★★★  starry night
★★  cartes du ciel
★  skysafari
★  kstars
★  nightshade
★  theskyx
  worldwide telescope

Your alternative for stellarium is not listed? Suggest!
Speaking about stellarium, one probably shouldn't forget about telrad.

Other search terms related to stellarium and their ratings are:
★★★★★ telrad
★★★★ nexstar
★ eqmod
You have in mind a companion for stellarium and it is not yet here? Propose!



Google Trends

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stellarium
celestia
starry night