From wilhelm@linmpi.mpg.de Tue Nov 18 16:47:21 2003
Date: Wed, 23 May 2001 14:07:17 +0200 (MET_DST)
From: wilhelm@linmpi.mpg.de
Reply-To: sumer-soft@esa.nascom.nasa.gov
To: sumer-soft@esa.nascom.nasa.gov
Subject: SUMER-SOFT: SUMER Radiometry

Subject: SUMER Calibration Programme 'radiometry.pro" in SolarSoft


 Dear colleagues,

 following the ISSI Workshop on SOHO radiometry in February 2001,          
 a critical re-assessment of the post-recovery situation was performed
 for SUMER. Although a perfect solution is still not available, 
 the following change has been implemented today (23 May 2001):

 Based on work by Schuehle et al. (ESA SP-463, 427, 2000) and              
 Pauluhn et al. (Appl. Opt. 2001, in press), an average loss in            
 responsivity of 31% will be assumed (based on 26% for He I,               
 28% for Mg X 609, 28% for Mg X 624, 34% for Ne VIII, 39% for N V,         
 and 29% for the Lyman continuum. The new uncertainties are very 
 conservatively estimated to be 33% (1 sigma) for detector A 
 and 36% for B. The values of 15% for A and 20% for B for pre-loss 
 periods have not changed (cf., Metrologia, 37, 393, 2000).  
 
 Use keywords EPOCH_7 (default) and BEFORE or AFTER as appropriate.        
 The calibration before the attitude loss is not affected. No new 
 restore files are required. To reproduce calibration work done with 
 keyword AFTER before 23 May 2001 set keyword EPOCH_6. Note that 
 a loss of 43% was assumed until then.  

 There was also a request to provide an option to calculate irradiances
 (keyword SUN_LINE) for 1 AU. This option (keyword IRRAD_AU) is now 
 available and is, of course, completely independent of the other change.

 If there are any difficulties, please, let me know.
 
 With best regards,
 
 Klaus Wilhelm