I am speaking about astronomical images not in general, but those taken with the Canon EF 17-40 f/4 L USM lens. They are almost always taken with the diaphragm

I am speaking about astronomical images not in general, but those taken with the Canon EF 17-40 f/4 L USM lens. They are almost always taken with the diaphragm wide open, and contain same kind of spikes -> spikes are not from diffraction.