Heavens-Above vs Sky Tonight

Heavens-Above provides satellite predictions and sky information through Android, iOS and web access. The website lists 10-day predictions for selected satellites, daily predictions for brighter satellites and Starlink passes from a launch. It also offers a live sky view, interactive sky chart, dynamic 3D Starlink orbit display and interactive 3D ISS visualization. Charts and information cover the Sun, Moon, planets, comets, asteroids and constellations. The Android app includes predictions for the ISS, visible satellites and radio satellites, plus orbit and ground-track views, night mode and an orientation-based tracker. Selected passes can be added to a device calendar. Predictions run locally, with a data connection needed every few days. The free plan costs nothing; Heavens-Above Pro costs $4.99, paid once and removes Android adverts. Predictions become less accurate farther from the current date.

Sky Tonight has no write-up on Specifiction yet; its figures are above.