Re: weak pixels, etc.

[Tom Droege <tdroege2@earthlink.net>]

Andrew and all,

You can tell which direction is which by looking at a saturated star.  The 
saturated stars smear out down a column.  To define row and column, rows 
are scanned out all at once, then you move down the column direction to the 
next row and scan it out.  Rows are overscanned.  We skip the first few and 
the last few rows.  We scan out 2064 pixels across the row, and then we 
scan 2037 rows.

I assume that the smear is down the column.  Hmmmm!  You are all reminded 
that I did some tests to find the best clock voltages to minimize what a 
saturated star did depending on where it was in the column.

With a little better definition of the problem I can go to the CCD-World 
list and ask for advice.

Tom Droege

At 12:17 AM 2/8/02 +0000, you wrote:

>Not in this case! The defect is hard to see on both the Darks
>and the Flats but is much more obvious (i.e. I found it when I
>knew exactly where to look) on an actual image. It looks as though
>electrons smear out over the full affected length of the column
>(or is that row? It's vertical on my plot: AXIS2 direction)