Re: What Is It

[Chris Albertson <chrisja@jps.net>]

aah@nofs.navy.mil wrote:
> 
> What spots are you referring to?  I see a couple of cosmic rays, and three splotches.
> The middle one looks like frost to me, and so I would suspect the others to be frost
> as well.

Frost seems reasonable running at < 0C in air but unless light is shinning on
the
CCD how can an obstruction on it's surface cause an image defect?  It is
brighter
in the center.  Could the ice be keeping the CCD warmer where covered?  Frost
would
be easy to prove/disprove, tempurature cycle the CCD and see if the "spots"
move.  

Do cosmic rays branch and cause Y shapped image defects?

> 

> , you had more than 32768 DN in each pixel, which seems
> abnormally high -- did you have the bias set properly? 

Tom,  As I understand it your -21000 pixel values are only 11000 counts above
minimum,
correct?  Doesn't your scale go from about  -32000 to +32000?  I want to make
certain I understand this.  


-- 
   --Chris Albertson             home: chrisja@jps.net        
     Redondo Beach, California   work: chris@topdog.logicon.com