StarTools

My friend and I do EAA, I don't think we're going to use astrophotography techniques like dithering.

We belong to a French EAA Forum but I live in Spain and do not know him. I can't see either his equipment or how he's using it. But these strange behaviors surprise me. This does not happen to me

If you have the same telescope you can think better of me about this walking noise.

I do have the ED50 and when used for 30 second exposures the images show the excepted distortions towards the edges and corners as I am not using a field flatener.
The centre of the image is OK here is the only process I have of roughly the middle of the frame and is only 21 light frames.
There is not the noise/distortion shown on the image you posted, though this image is cropped so the stars on the full image do elongate more towards the corners.