Help with Aberration

[nightster]

Just added a CCDT67 to the image train of my RC6. Love the FL (983mm as determined by Plate Solving.) Attatched are the corners of a stack of L that I was working on from data this weekend. Cocoon Nebula. Getting some interesting aberations in the corners. Hoping to get some input on what it may be and what I could do about it.  

-Jeff

[sharkmelley]

First check there are no aberrations without the CCDT67 in place.

Secondly check the distance of the sensor from the reducer. 

Thirdly check that neither the reducer nor the sensor is tilted with respect to the main optical axis of the scope.

Mark