Yeah, that's a hard definition. There are great ATMs who are average (or worse) observers. Great observers who have trouble replacing a screw in their mounts. Fantastic imagers who couldn't find Vega without a computer. etc.
And "pure observing" is a (relatively) recent trend. Someone who quietly amasses thousands of variable star observations but never looks at a DSO or takes a photo contributes much more of actual value to others. The fact that a keen eyed observer may optimize their craft, location and gear such that they can see a 17th magnitude glob in another galaxy is incredible to me. But not of much intrinsic value to the world.
We probably all have our definition of great. I'd say a great amateur is someone who is both helpful to others and fun to spend an evening observing with. If you can learn something from someone whose presence improves the experience, that's great.
Edited by bunyon, 21 July 2021 - 05:14 PM.