[Aavso-photometry] average vs. median

[arne]

Ben Davies wrote:
> What exactly are cosmic rays anyway?   I put a thin lead sheet over my 
> ccd and they seem to zip right through it.  So they must not be alpha 
> particles.  And I would think that x and gamma rays are too far blueward 
> to be detected. What's left?
> 
> And whatever they are, are they always going to leave bright, obvious 
> tracks, or are many going to go unnoticed on visual inspection?
> 
where are you located, Ben?
Remember, cosmic rays come from all directions, so you would have
to totally encase the CCD in order to prevent them.  Even common
things like concrete and UBK7 glass give off radiation that is
easily detected by CCD cameras.  An interesting email:
http://www.ctio.noao.edu/pipermail/ccd-world/2001/000474.html

The amount of deposited energy changes too.  Some are point sources
and bright, some are nearly parallel to the front surface.

Fun things to study if you were a high-energy physicist.  To me,
cosmic rays are "vermin."
Arne