That's a good tip about the lens hood. Get one and use it but remember to remove it for flash photography or you;ll get shadows over the pic.
I didn't look closely at the shot to work out it was the comet! Thought it was a plane flying over and I was spewing the other night that i'd missed seeing it.
If you want a challenge, get yourself onto the startline at WSID and try to take shots of white cars, at night, with their headlights beaming