I wondered about dark frames taken for astro imaging &
where those rays really came from -
were they cosmic rays or background radiation but then I found out that
some camera lenses are radioactive - in this case Thorium is the culprit used in the glass.
There is a good video about it on Youtube:
I wonder how many other manufacturers use radioactive glass?
Could it be on some coma correctors?
It can't be good for your delicate CCD sensor &
would cause all sorts of annoying streaks in the dark frames & the light frames
basically corrupting your data.
Does anyone know?
cheers
Allan