Astro App is described as 'The Astro App is a tool for exploring the night sky and tracking celestial events. It's primarily targeted for amateur astrophotographers' and is an website in the education & reference category. There are six alternatives to Astro App, not only websites but also apps for Windows, Linux, Mac, Flathub and Flatpak. The best Astro App alternative is Siril, which is both free and Open Source. Other great sites and apps similar to Astro App are DeepSkyStacker, FITS Liberator, SAOImageDS9 and PixInsight.