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Date: Wed, 11 Sep 1996 13:27:16 -0400
From: asquared@ricky.harvard.edu (Anastasia Alexov)
Message-Id: <199609111727.NAA02845@ricky>
To: axaf@ricky.harvard.edu, asc@ricky.harvard.edu
Subject: 82 HSI GRATINGS IMAGES ==> TOGA MOSAIC !!!!
X-Sun-Charset: US-ASCII
Status: R


		-------------------------------------------
		82 HSI GRATINGS IMAGES ==> TOGA MOSAIC !!!!
		-------------------------------------------

There has been an INITIAL pass at mosaic'ing the HSI rehersal data.  The
VERY COOL resultant TOGA mosaic can be found in: 

	/proj/asc2/vriprod/960823 - hsiallstage.qp
	
	/proj/asc2/vriprod/960823/hsi_piperun - hsi*epr.qp
		all the component files.
		

If you're going to do more that just stare at the image in awe, please
read the following notes on the data; otherwise, enjoy the view!!

///////////////////////////////////////////////////////////////////////////

Things to be aware of, regarding the data set:

1) The raw data files can be found in /proj/asc2/hsi2/vritest/data/960823.

2) The component data files "hsi*epr.qp" are the results of running Level 0
   and Level 1 processing:  	
	- Decommutate HSI lab data and create a processed raw data file.
	- Update event header with test parameters from a staging par file.
	- Read the input event list degap correct the events, compute 
	  detector, tangent detector, and undithered (x,y) coordinates, 
	  add time to the event list, degap correct the events.

3) The stage logs are interpreted and each component image gets an offset
   depending on the stage information.  Once all the images have the 
   'correct' offset, the event files are appended in order to create the
   resultant TOGA event file. 
   NOTE:  the parameters were not tuned for stage offsets, since this is
	  the initial pass.
   The stage logs can be found in /proj/asc2/vritest/960823/logs

4) This TOGA image contains all but component files except for the 102648
   data file.  We did not have a stage log at the time of the first mosaic
   runthrough.

5) The component data files for that night are broken up into 3 groups:
	 102567-102602    minus orders, including 0th order;  small steps
	 102603-102647	  plus  orders, including 0th order;  small steps
	 102648		  0th order; LETG +-1st orders

    However, there are large steps in the stage movement that take place, in
    between these three data groups.  This large stepping, may be the cause
    to the misalignment of the resultant TOGA image.
					
    To see see the misalignment problem:
    	- center about the 0th, +-1st LETG orders with minimal blocking 
	- note that the minus arm is lined up with the 0th order
	- note that the plus arm is off by ~30 pixels from the 0th order

6) There are also some other image alignment problems due to using only
   the default (not tuned) parameters in this runthrough.  Viewing an
   unblocked +1 or -1 HEG  will show a double line and double peak at
   the center of the order.

7) The data has not been corrected for a 1 degree shift necessary to
   correct for the HSI vs stage alignment.  Therefore, the arms have 
   a ~1 degree drop off (plus side)/raise (minus side).  This is most
   evident at the tail ends of the orders on both sides - the arms do
   not look straight at the wings of the image.


We are working at fixing all these problems.  Please stay tuned.  

Doug McElroy, Anastasia Alexov