In our astronomy club there are a few stalwarts stubbornly clinging to "The Guide" for their electronic charting (even though development for this app has been dead for years). In years past, their arguments for staying-put have gradually been eroded thanks to the continual and consciously excellent improvement of Sky Safari. It seems, now, that the argument comes down to pretty much one point: "(whiny voice/on)... but Sky Safari doesn't allow user- definable field rotation ..(whiny voice/off).".
I too would really like to see this feature added to Sky Safari. (Before someone fires-up with: "Just rotate your tablet, dumba$$!" , not so easy, when your tablet is mounted on your secondary cage. )
Please consider adding this feature to your already excellent app.
(If anyone else would also like to see this, please chime in)