RE: The promised format

[Michael Gutzwiller <deepsky@fuse.net>]

I have looked at the images and can give some clues about where the problem
may lie and where the imaging pixels are.  I analyzed the first 7 columns
and last 6 columns of image H3R1836.529.  Here are the results:

Column	Median	Noise
   0		 7860		 95.8
   1		 6375		  1.8
   2		 7271		  7.1
   3		 6374		  2.1
   4		 7424		 32.2
   5		 6375		  2.1
   6		10466		 55.9
2037		10328		 84.5
2038		 7675		 69.3
2039		11109		128.7
2040		 7508		 67.2
2041		 7508		 67.2
2042		 7524		 66.8

Column 6 is the first imaging pixel and column 2037 is the last imaging
pixel.  Looking at the images I can see stars in these columns.  This gives
the 2032 imaging pixels we expect.  I really don't understand the other
columns in relation to what Tom describes below.  One thing I did see is
that column 2041 exactly duplicates column 2040.


Thanks,

Mike G.

-----Original Message-----
From: owner-tass@listserv.wwa.com [mailto:owner-tass@listserv.wwa.com]On
Behalf Of Tom Droege
Sent: Thursday, December 07, 2000 12:54 AM
To: tass@listserv.wwa.com
Subject: The promised format


OK, Herb Johnson has captured my previous note on what I am writing, and
put it in TN-71.  This is repeated below.  So you don't have to wait until
tomorrow.

Arne and all,

Well, I can give you a breakdown of where I think the overscan and dark
pixels are, but it is clearly wrong. I have pretty much followed Arne's
request, and there are overscan and prescan and covered pixels in the
format. But I am making an error somewhere. I am not quite looking where I
think I am looking. It is just one of those things that takes a few days of
prom burning to straighten out. This is just not the type of thing that is
on top of my priority list. It is something that I know can be solved.

One of you may get to solve it if you really care.

OK, you may recall that the CCD442A has 16 front end pixels, 8 covered
pixels, 2032 live pixels, and 8 more covered pixels.

Here is what I am trying to do:

Skip 8
Read 2 pre scan pixels
Skip 8
Read 2 covered pixels
Skip 4
Read 2034 covered pixels
Skip 12
Read 2 over scan pixels

You will note that this adds up to 2040. Yet I am reading 2043 pixels. It
could be an error in how I code the prom, or it could be an error in the
BASIC transfer code.

Note from Herb: a number of TASS members have reported that the first 6
columns and the last 2 or 3 columns of the images on CD #5 are clearly NOT
imaging columns.

OK, this is where we stand.  I will not turn my attention to writing up
everything.  Perhaps someone can detect the problem.

Tom Droege