Hi Rich,
Thats a fine horsehead, looks like the seeing was very good that night as well....
well done, Wish I could get that in 1min subs!!
I get a 5th spike as well in my newt, at the 45 degree spot and mine is caused by the focuser tube which sticks inside the OTA by about 2cms. When my MPCC turns up I hope that the extra back focus shall bring it out and hopefully no 5th spike..
Sometimes the mirror cell clips will do this too I have heard?
Cheers and happy new year!!
Gary