Why?

[mudman]

i was out yestetrday afternoon looking fror some nice evening light.
I took this multi image with camera on a tripod, apeture mode, using a wireless relaese.
this SHOULD have given a sharp image as there was no contact whatsoever with the camera while exposures taken. there was no wind no cause movement either.
So why is it not sharp?
I know i cut off the top of the tower but the sharpness is the problem here.
all help appreciated
cheers