OBJECT     = INSTRUMENT                                                       
INSTRUMENT_HOST_ID             = OAO                                          
INSTRUMENT_ID                  = OASIS                                        
                                                                              
OBJECT     = INSTRUMENT_INFORMATION                                           
INSTRUMENT_NAME = "Okayama Astrophysical System - IR Imaging & Spectroscopy"  
INSTRUMENT_TYPE                =  CCD                                         
INSTRUMENT_DESC                = "                                            
                                                                              
Instrument Overview                                                           
===================                                                           
                                                                              
The impact of comet Shoemaker-Levy 9 with Jupiter was observed by             
using OASIS (Okayama Astrophysical System for Infrared Imaging and            
Spectroscopy) at cassegrain focus of the 188-cm telescope of Okayama          
Astrophysical Observatory (OAO), which is a branch of National                
Astronomical Observatory of Japan (NAO).                                      
                                                                              
Scientific Objectives                                                         
=====================                                                         
                                                                              
To observe the impact of comet Shoemaker-Levy 9 with Jupiter by               
using OASIS (Okayama Astrophysical System for Infrared Imaging and            
Spectroscopy) at cassegrain focus of the 188-cm telescope of OAO.             
                                                                              
Calibration                                                                   
===========                                                                   
                                                                              
The impact of fragment K was predicted at 10h18m UT, July 19, 1994. We        
used a filter with centered wavelength of 2.35 micron (FWHM 0.05 micron)      
to take images continuously. In each frame, Jupiter and two Galilean          
satellites, Io (left) and Ganymede (right), were seen. We used Io as a flux   
calibrator. Flux from Io was estimated at 7.8x10^-12 W m^-2 micron^-1.        
                                                                              
Operational Considerations                                                    
==========================                                                    
                                                                              
The integration time occasionally varied due to some instability              
of the control system of the OASIS. Each image was bias subtracted, flat      
fielded and corrected for bad pixels. The top of each frame is north.         
These observations caught two precursors: the main event and the shoulder     
of the K impact. We used two ND filters, whose transparencies are 10% and     
2%, to prevent the OASIS from saturation due to the brighter main event.      
                                                                              
Detectors                                                                     
=========                                                                     
                                                                              
The OASIS is a 256 x 256 NICMOS3 (HgCdTe) array. One pixel of the OASIS       
corresponds to 1.0 arcsec.  This infrared camera allows imaging from 1-2.5    
micron with a high dynamic range.   The pixel size is 40 micron.              
                                                                              
Optics                                                                        
======                                                                        
                                                                              
OASIS at cassegrain focus of the 188-cm telescope of Okayama                  
Astrophysical Observatory (OAO)                                               
                                                                              
Filters                                                                       
=======                                                                       
                                                                              
 wavelength/micron                                                            
 1.70 (methane band)                                                          
 2.17 (hydrogen band)                                                         
 2.35 (methane band)                                                          
 1.50 (ammonia band)                                                          
 others (continuum)                                                           
                                                                              
Field of View                                                                 
=============                                                                 
                                                                              
View of the OASIS is 4.3 arcmin x 4.3 arcmin, covered by 256 x 256            
NICMOS3 (HgCdTe) array. One pixel of the OASIS corresponds to 1.0             
arcsec. The OASIS was at final stage of its making for the SL9 impact.        
                                                                              
"                                                                             
END_OBJECT = INSTRUMENT_INFORMATION                                           
                                                                              
                                                                              
OBJECT     = INSTRUMENT_REFERENCE_INFO                                        
REFERENCE_KEY_ID               = "WATANABEETAL1995"                           
END_OBJECT = INSTRUMENT_REFERENCE_INFO                                        
                                                                              
END_OBJECT = INSTRUMENT                                                       
END