It fails with: Code: mapplauncherd[13660]: Booster: Failed to invoke: Booster: Loading symbol 'main' failed: '/usr/bin/stellarium: undefined symbol: main' Changing Code: X-Nemo-Application-Type=silica-qt5 to Code: X-Nemo-Application-Type=no-invoker in your desktop file will help. And one more thing: please don't upload split tar files as sources to github, but upload the source tree and additional commits itself.
mapplauncherd[13660]: Booster: Failed to invoke: Booster: Loading symbol 'main' failed: '/usr/bin/stellarium: undefined symbol: main'
X-Nemo-Application-Type=silica-qt5
X-Nemo-Application-Type=no-invoker