[gregbradley]

I have been doing a lot of squaring up of my cameras with my RHA which really shows up poor squareness on the stars especially in the corners.

The difference between unsquared and square is very pronounced. Stars are way smaller, look more firey and the overall look to the image is much like the difference between poor seeing and great seeing.

I am now wondering how much of the sharpness are we giving away with slower scopes where this nonsquareness is less visible but still there.

So if you are spending a lot of time collimating your compound scope to get it really spot on spend some time also inspecting tilt in your camera. Not all sensors are laid dead level either.

It may sharpen up your images and get round stars to the corners. Some of that star elongation may not be tracking error at all but lack of squareness of your camera. Its caught me out a few times thinking I was getting tracking errors when it was errors in orthogonality.

Greg.