I have these weird spikes in my calibrated images. I am shooting mono with Antlia SHO with a QHY 294m pro.
The Ha looks fine but the s2 and o3 have the artifact. I went back and looked through the single images at it looks like it is in the light frames albeit very faint. The flats and darks look ok.
Not sure if this a light leak around the filter or what would give this effect.
That is the middle or end star of the belt just slightly out of your field of view and the light is hitting the edge of the filter and causing a flare. I have seen this myself a bit over the years.
