SINFONI has four gratings, (see the User Manual for details concerning grating properties). Our QC1 checks for the dispersion using arc frames can be divided in several categories:

• PRODUCT QC PLOT. For each dark pipeline product and its associated raw frames we create a plot with the most significant features.
  
  
• DIFFERENCE FRAMES. A simple and efficient method to check short-term and long-term variations is to construct difference frames
  
• TRENDING This means that selected QC1 parameters are monitored as a function time. The purpose is to find long term variations which cannot detected on a single product frame.

The wavelength recipe (sinfo_rec_wavecal) generates several QC1 parameters, that are dependent on the grating (INS.GRAT1.NAME, four different ones in use) and the camera (INS.OPTI1.NAME, three different one in use).

The QC plots summarize the most important characteristics for a wave product.

• Example SI_WAVE
• Most recent SI_WAVE [PS]
  
  Figure caption

Upper: The first coefficient of the wavelength calibration polynomial (the wavelength offset) for all columns.	Upper: Slit_pos, the absolute column positions of the 32 slitlets (start and end). The start is shown against the end position, and a linear regression.	Upper: As Upper left: The first coefficient of the wavelength calibration polynomial (the wavelength offset) for all columns (RED); The same of the reference frame (BLUE)
Middle: The second coefficient of the wavelength calibration polynomial (the linear dispersion) for all columns.	Middle: The residuals of the linear fit shown in the upper plot are given.	Middle: As Middle left. The second coefficient of the wavelength calibration polynomial (the linear dispersion) for all columns (RED). The same for the reference frame (BLUE)..
Bottom: The third coefficient of the wavelength calibration polynomial (the quadratic term of the dispersion) for all columns.		Bottom: As Bottom left. The third coefficient of the wavelength calibration polynomial (the quadratic term of the dispersion) for all columns (RED). The same for the reference frame (BLUE).

Inspection of arc product difference frames is a valuable way to check on the grating position.

• Current Product minus Last (Most Recent) Product shows the short term variations (ldiff)
• Current Product minus the reference product

Trending describes the variation of a QC1 parameter with time. Trending plots don't consist of control limits. Their purpose is more to document long term changes of QC1 parameters, which cannot be detected in process control charts. Trending plots can be subject of 'time variation analysis'. The same QC1 parameters as the ones shown under the 'control chart' section are trended. More parameters are available via the interfaces of our QC1 parameter database.

The wave recipe returns a number of QC parameters, among them the average and median coefficients of the wavelength solution. The measured wavelength is compared against the encoder value (INS.GRAT1.WLEN) and the nominal values (e.g. 2.2000 for the S3_K grating). During commissioning, the SINFONI gratings have been initialized, that the average of the central wavelength coincides with the nominal value.

• Resolving Power: We trend the resolving power as the FWHM of the found arc lines divided by the central wavelength.
  
  
  • WAVE_RP
    
    
  • WAVE_RP H
  • WAVE_RP J
  • WAVE_RP K
  • WAVE_RP_H+K
    

• Offset : between central wavelength as returned by the wavecal recipe
  and the grating encoder value. (Measured Minus Encoder)
  Assuming the grating initializes with the same encoder value, this parameter nominally measures the intrinsic errors of the pipeline recipe.
  
  
  • WAVE_OFPI
    
    
  • WAVE_OFPI H
  • WAVE_OFPI J
  • WAVE_OFPI K
  • WAVE_OFPI H+K
    
    
• Offset between nominal central wavelength (as given by 1.250 J, 1.650 H, 2.200 K, 1.950 H+K)
  and the measured ones as given by the wavecal recipe in pixel.(Measured Minus Nominal).
  This value monitors the offsets against the nominal values..
  
  
  • WAVE_OFNO
    
    
  • WAVE_OFNO H
  • WAVE_OFNO J
  • WAVE_OFNO K
  • WAVE_OFNO_H+K
    
    
• Offset between encoder value and the nominal central wavelength (as given by 1.250 J, 1.650 H, 2.200 K, 1.950 H+K).(Enoder Minus Nominal).
  This value monitors the position stability/variability of the grating.
  
  
  • WAVE_OFNO
    
    
  • WAVE_OFE_H
  • WAVE_OFE J
  • WAVE_OFE K
  • WAVE_OFE_H+K
    
    
• Dispersion Coefficient in micron/pixel monitored for three pre-optics separately
  
  
  • WAVE_DISP H
  • WAVE_DISP J
  • WAVE_DISP K
  • WAVE_DISP H+K
    
• Arc lamp intensity (max and mean from off-lamp subtracted raw frame)
  
  • Mean
  • Max
    
• X-Position of the right edge of slitlet #17, as derived from the SLIT_POS product
  
  

• WAVE_SLIT_POS