I have been taking a few astro photos on a very high ISO, and have found what I think to be a few hot pixel. I though at first that I had managed to get a few very sharp pic of some red and blue stars. But now I have tried doing some stacking It seems that they are static to the rest of the moving sideways.
The thing that may have thrown me is that I thought that a 'hot pixel' was just that. A pixel, but it also seems to bleed outwards to make a small circle of a few faded pixels either side. Here is what I mean:
The image was saved as 'fine' quality on a D90 on a 2500mm telescope (1250mm with 2x teleconverter).
So are these hot pixels?