Hi,
I have an iPad 2 with iOS 9.3.5. When I use the Sky Safari Plus help system and choose "Quick Start", that works properly. If I choose "Introduction", I'm brought back to the Apple App screen. If I choose "Basic Concepts" I'm brought to the next page of choices, but if I choose for example "How Stars Die", the app crashes back to the Apple App screen.
You have to forgive my ignorance as I am new to Apple hardware as this iPad was given to me and I'm used to a Windows operating system. So I'm not sure if the correct term is crashing as Sky Safari isn't disappearing when the Help issue occurs. I can bring the app full screen again by double clicking the home button on the iPad and then tapping the Sky Safari app.