Thanks Glen, I'll work with that - we might be in clear(ish) skies tonight.
But, in truth, I need the "Estimation for Dummies"
version. Eg:
1. Can you see Epsilon Crucis (marked "1" on reference map), then limiting magnitude is X
2. Can you see (a fainter object, but one whose location can be easily located - say half way between two bright stars) - marked 2. on map, then limiting magnitude is Y
3. Can you see etc.
I'm sure some of you guys have such a protocol in your heads. I'd think that many of us would benefit, not only me.
Cheers
Eric
