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I can only recommend to go back to basics and start from the ground up due to this image having multiple possible issues as mentioned by Chris and Ryan
1/ Level tripod and set up with front leg facing True South then install mount and scope
2/Check payload on mount is balanced in Ra and Dec ( adjust slightly east heavy , move counterweights no more than 10 to 15mm )
3/ Set mount to Home Position
4/ Check Secondary and Primary mirror is clean
5/ Collimate Newt using both a Cheshire and Laser ( ensure primary mirror is not pinched, ensure secondary mirror is not slight tilted with respect to the focus tube )
6/ Ensure camera and coma corrector are fitted with correct manufacturers distance to camera sensor
7/ Ensure camera and coma corrector sit level in focuser without tilt
8/ Polar align to under an arc minute
9/ Perform a Star test ( slew to a bright star say magnitude 1.0 to 2.0 and take 10 sec, 30 sec and 60 sec subs unguided ) Check images and ensure star is round and has 4 diffraction spikes not 6 or 8
If more than 4 , secondary mirror may have tilt or spider vanes could have an offset )
10/ Run your guiding to ensure guiding error is under 1 arc sec
11/ If all of the above is ok , then image say M42 again , this time take 60 sec subs , review images and then if ok image with longer subs 2 or 3 min
Caveat
Avoid imaging during cloudy weather even high cloud
Avoid imaging in windy weather with newts ( they act like a sail )
Hope the above offers some practical advice moving forward
Cheers
Martin
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