Subject: HRI-SIM TV1 Flash Report                                             
Date: Thu, 27 Jun 2002 23:25:25 -0400 (EDT)                                   
From: Dennis Wellnitz <wellnitz@astro.umd.edu>                                
                                                                              
Hi all,                                                                       
                                                                              
I have gotten no message that anyone doesn't want to be on this mailing       
list, so everyone is still on it.                                             
                                                                              
On Wednesday we discovered that the automatic liquid nitrogen re-filling      
system for the Ball 8 thermovac chamber kept turning itself off, so we        
had to keep it topped up manually.  Today we were able to work around         
the problem, so the automatic system is once again working.                   
                                                                              
Cooling proceeded well overnight, permitting us to obtain marginally          
unsaturated images in the morning.                                            
                                                                              
In the early afternoon we changed over from liquid nitrogen cooling of        
the liquid helium cold plate to cooling it with liquid helium, increasing     
the rate of cooling of the IR FPA detector and the SIM bench.                 
                                                                              
At about the same time, the IR FPA had cooled sufficiently that we could      
begin looking for light.  We found light on the first image we took with      
illumination, but it turned out that it was a reflection rather than          
the main beam.  We spent the rest of the day (until about 8 pm MDT)           
refining the alignment and focus of the external telescope and illumination   
system.                                                                       
                                                                              
During that data taking we were able to discern the CO2 absorption            
at 4.25 microns, and the H2O complex around 2.67 microns, and verify          
that they were within a few pixels of their intended locations.  The          
slit also appears to be well-focussed on the detector, and one end of         
the slit is within a few pixels of the edge of the detector, permitting       
us to differentiate within-slit illumination from within-spectrograph         
illumination.  We are able to see the black body radiation of the room        
at the longer wavelengths.                                                    
                                                                              
Tomorrow we plan to sort out some multiple reflection or multi-image          
problems, and continue the alignment of the external telescope to the         
SIM.                                                                          
                                                                              
It appears that we are still on track to finish all cold measurements         
before July 4.                                                                
                                                                              
Please let me know if you have any questions or comments.                     
                                                                              
Because I am flying away to attend the Contour launch at Kennedy Space        
Center, the next Flash Report will be prepared and sent out by Don            
Hampton or his designee.                                                      
                                                                              
        Dennis