I do not see any code issue with it.
However another option would be the use of a 3 way switch (SPDT)
Common to contactor coil.
One terminal from constant feed.
One terminal from red of the photo cell.
You end up with ON or AUTO with this set up and no back feed to the red of the cell.
Make sure the EGC is large enough.
Bob
[This message has been edited by iwire (edited 11-07-2005).]