It's a cracking achievement and a very nice pic too.
One observation I do have - and I don't want this to be taken in a negative way because it is just an observation, is that the pic was taken from a plateau at roughly 1 mile altitude if i'm not mistaken. Now with increasing altitude this will give the 'effect' of having a lower horizon hence like observing from further north (if you are looking north and spotting NLC). I'm sure there's some formula out there to work out as your altitude increases the amount your 'virtual' latitude increases by.
I wonder as we see the southern boundary record being broken in the future if it will correspond to a further increase in altitude?