[pmrid (Peter)]

I'm hoping someone out there knows something about this. I'm having a ' discussion ' with the manufacturer of one of my CCDs. I sent them some 10 and 20 minute dark subs showing what people keep telling me are cosmic ray hits. They are streaks of varying lengths and shapes in locations that vary from sub to sub. Those on the 20 minute subs are 3 or so times longer than those on 10 minute subs.

The manufacturer repeats the usual mantra aout cosmic rays being normal and insisting that the streaks on the longer subs are also not out of the ordinary.

But can anyone with actual knowledge comment on this. Cosmic rays/muons travel at 28.9 cm/ns gve or take a bit - measured at sea level ( according to a paper from RMIT). Thats aboutb1.07 billion km/hr. At that speed they would hit and pass through a CCD substrate in the minutest period of time. That being so, how dos that stack with the conventional wisdom from this manufacturer about long streaks correlatng with lnger exposures?

Can anyone add to or explain this?
Peter