Astronomy teachers struggle to explain counterintuitive lunar concepts like why the terminator appears curved when viewed from Earth.
Create a web-based simulator with adjustable viewing angles and lighting to demonstrate lunar phases in real-time.
Schools and planetariums would license this for classroom use, while individual educators might pay for personal access.
The MVP could be a simple 3D web renderer with preset viewing scenarios.
Risk: Niche market with limited repeat customers unless expanded to broader astronomy topics.