From WILHELM@sumop1.nascom.nasa.gov Tue Nov 18 16:46:07 2003
Date: Thu, 21 Oct 1999 12:54:57 GMT
From: WILHELM@sumop1.nascom.nasa.gov
To: CURDT@linax1.MPAE.gwdg.DE, GABRIEL@ias.fr, grewing@iram.grenet.fr,
     hassler@boulder.swri.edu, hollandt@chbrb.berlin.ptb.de,
     mhuber@estsa2.estec.esa.nl, jordan@stars.gsfc.nasa.gov,
     kuehne@chbrb.berlin.ptb.de
Cc: WILHELM@sumop1.nascom.nasa.gov
Subject: SUMER-SOFT seems to be down. So I send this to my other SUMER lists.

Subject:  TL_SUMER.PRO


Dear colleagues,

during the June 1999 SUMER campaign, I tried to adjust the SUMER slits as best
as I could in spatial (and spectral) direction. The slits #1, 2, 4, and 7 
(centred on the detector) did not pose any serious difficulties, but the slits 
on the upper and lower portions of the detector did. Slit #8 was well adjusted 
provided slit #7 was, but slit #5 was not unless its global position parameter 
was changed from 218 to 246, which I did. Note, however, that this adjustment 
is strictly valid only for one wavelength (1152.151 A) as the spectrum is not 
perfectly parallel to the detector spectral pixel direction. While I was 
working on TL_Sumer (and SCL_Convert_UDP), I corrected a few minor inaccuracies,
which should have no impact on most of the SUMER sequences under preparation 
with a few possible exceptions: 

1. The lower wavelength limit of detector B is now at 346 A (from 340 A) in 
second order in line with the SUMER simulator and the onbaord hardware and 
software. (We had out-of-limit errors before.) 

2. The situation for slits #3 and 6 is very difficult. I considered it for a 
long time before deciding on the change descibed here. These slits are 
severely vignetted, if read out with the 120-spatial window. Since the 
upper portion of the detector is occulted by a slit cone onboard, 
no acceptable adjustment was possible. There is, however, the option of using 
the 360-spatial window, if the telemetry rate is not a concern. I have,
therefore, changed the default value of the spatial window for slits #3 and 6 
to 360. Of course, you can override that, but if telemetry rate is of the 
essence, it might be better to go to slits #5 and 8.

3. Although I probably mentioned it some time ago, the slit recommended for
use with the rear slit camera is now #4. The revised TL_SUMER calls this slit 
by default.
 
With best regards,
Klaus Wilhelm