Subject: HRI-SIM TV2 Flash report                                             
Date: Fri, 23 Aug 2002 02:10:17 -0400                                         
From: Dennis Wellnitz <wellnitz@astro.umd.edu>                                
                                                                              
Hi all,                                                                       
                                                                              
Last night during instrument shut-down, we had a bit of problem with the      
ITOC, specifically, the GPIB interface to the power supplies did not          
respond to the power-down command.  As a result of investigating and          
dealing with this problem, we were not able to continue with calibration      
work until about 4:00 pm MDT today (Thursday).  However, we were able to      
conclude calibration work at about 11:00 pm MDT tonight, perform              
instrument shut-down without a problem, and commence warm-up.                 
                                                                              
Today we continued calibration work by taking data on the SIRTF               
blackbody at settings 300 and 400, and then addressed linearity by            
increasing exposure time.  Both data sets appear to be entirely adequate      
for their purposes.  We then investigated a couple of different ways to       
reduce the long-wavelength signal and increase the short-wavelength           
signal to provide a flatter spectrum for flat-field corrections and to        
increase signal-to-noise at the short wavelengths.  As 11:00 pm               
approached, we checked the list of procedures, and determined that all        
of those which had not yet been addressed at this SIM bench temperature       
could be addressed at the remaining SIM bench temperatures planned for        
next week.  We therefore concluded that we could indeed terminate the         
current calibration work, and begin warm-up.                                  
                                                                              
We plan to convene again at 9:00 am MDT Saturday morning (August 24) to       
perform safe-to-mate on the CCD system, check stimulator signals and          
connections, and check that everything is ready for re-closing the            
chamber and starting cool-down.  We plan to track the performance of the      
CCD system as it cools over Saturday and Sunday by taking data every 10       
degrees C.  By Monday we expect to begin operating the IR-FPA and             
re-aligning.                                                                  
                                                                              
Unless something very interesting happens in the interim, I plan to           
issue the next HRI-SIM TV2 Flash report on Sunday evening (August 25).        
                                                                              
Please let me know if you have any comments or questions.                     
                                                                              
If you would prefer not to receive these Flash reports on HRI-SIM TV2,        
please let me know.                                                           
                                                                              
                Dennis