From: "William A. Podgorski" <wap@cface4.harvard.edu>
Message-Id: <9703271419.ZM6378@cface4.harvard.edu>
Date: Thu, 27 Mar 1997 14:19:00 -0500
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To: jerius@cfa.harvard.edu, gaetz@cfa.harvard.edu
Subject: EKCHDOS06
Cc: mfreeman@vger.harvard.edu, lcohen@cfa.harvard.edu, redgar@cfa.harvard.edu,
        wap@cface4.harvard.edu
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Terry, Diab,

I have taken a look at the EKCHDOS06 mirror database and concluded that
it is OK and should become the new baseline. I used Terry's version,
which is located in:


     /proj/axaf/simul/databases/mirror/EKCHDOS06/EKCHDOS06*.rdb

I made a series of raytrace studies which are located in:

     /ceaxaf1/ekc/HRMA_models/EKCHDOS04
     /ceaxaf1/ekc/HRMA_models/EKCHDOS05
     /ceaxaf1/ekc/HRMA_models/EKCHDOS05_low
     /ceaxaf1/ekc/HRMA_models/EKCHDOS06

The first set is our previous baseline, and yields images which look
familiar to us(see EKCHDOS04_N.ps where N=shell#). The images are displaced
downwards from the horizontal axis.

The second set of raytraces is in EKCHDOS05. These use Terry's new mirror
database with the decenters derived from the off-axis HSI images. If you look
at these figures you see that they are different from the EKCHDOS04
images in that the images are more symmetric about the horizontal axis,
as compared with the EKCHDOS04 images, which drooped downward. These images
are EKCHDOS05_N.ps .

To examine this, I ran raytraces using EKCHDOS05 but with low order
axially symmetric mirror deformation files. These results are in
EKCHDOS05_low. The images are in EKCHDOS05_low_N.ps . We see that these
images are displaced above and to the left ( I have flipped the x
axis for these plots). So the combination of these image displacements
with the EKCHDOS04 images will be more symmetric about the horizontal
axis and displaced to the left.

Finally, I ran EKCHDOS06 over all 4 shells with full mirror maps, including
both the revised axial positions of the optics from Kodak measurements and
the offset cone angle full mirror maps to give the proper relative
focus positions shell-by-shell. These maps are in:

     /ceaxaf1/ekc/HRMA_models/sums/xy_xrcf_sum_off.BSPL

          where x =  {p,h}
                y =  {1, 3, 4, 6}

The images are EKCHDOS06_N.ps . Comparison of these images with the images
in EKCHDOS05 shows that they are very similar, so the change in image
characteristics is due to the decenters and not the focus changes.

The focus results (using OSAC Focus Module) are as follows

 Shell    Absolute   Relative (OSAC Z)  Target(XRCF meas)
     1  10275.0342      0.3047             0.302
     3  10274.7295      0.0000             0.000
     4  10274.4551     -0.2744            -0.277
     6  10274.8730      0.1436             0.152

So we have the focus correct.

An issue for another day is to examine the XRCF on-axis images to
determine if they match the raytraced images. I have started to
do this but have no conclusions as yet.

Bill

PS: I will put the new mirror maps in /proj/axaf




-- 
===============================================================================
William A. Podgorski                Harvard-Smithsonian Center for Astrophysics,
                                       Smithsonian Astrophysical Observatory
Email: wpodgorski@cfa.harvard.edu   60 Garden Street, MS 5
Phone: 617 495 7363                 Cambridge, MA  02138
FAX:   617 495 7098                 USA

