PixInsight Not Preserving Original FITS Header Information

[twade]

To PTeam,

I just noticed PixInsight is not preserving the original FITS header information.  For example, here's the original FITS header information:

SIMPLE     = T                                                  
BITPIX     = -32 /8 unsigned int, 16 & 32 int, -32 & -64 real    
NAXIS      = 2 /number of axes                                  
NAXIS1     = 4096 /fastest changing axis                          
NAXIS2     = 4096 /next to fastest changing axis                  
BSCALE     = 1.0000000000000000 /physical = BZERO + BSCALE*array_value          
BZERO      = 0.00000000000000000 /physical = BZERO + BSCALE*array_value          
OBJECT     = '        '                                                            
TELESCOP   = '        ' /          telescope used to acquire this image            
INSTRUME   = 'Finger Lakes'                                                        
OBSERVER   = '        '                                                            
NOTES      = '        '                                                            
DATE-OBS   = '2008-04-03T06:13:33' /YYYY-MM-DDThh:mm:ss observation start, UT      
EXPTIME    = 600.00000000000000 /Exposure time in seconds                        
EXPOSURE   = 600.00000000000000 /Exposure time in seconds                        
SET-TEMP   = -35.000000000000000 /CCD temperature setpoint in C                  
CCD-TEMP   = -35.062500000000000 /CCD temperature at start of exposure in C      
XPIXSZ     = 9.0000000000000000 /Pixel Width in microns (after binning)          
YPIXSZ     = 9.0000000000000000 /Pixel Height in microns (after binning)        
XBINNING   = 1 /Binning factor in width                        
YBINNING   = 1 /Binning factor in height                        
XORGSUBF   = 0 /Subframe X position in binned pixels            
YORGSUBF   = 0 /Subframe Y position in binned pixels            
FILTER     = 'Lum     ' /          Filter used when taking image                  
IMAGETYP   = 'Light Frame' /       Type of image                                  
OBJCTRA    = '12 34 14' /          Nominal Right Ascension of center of image      
OBJCTDEC   = '+10 31 35' /         Nominal Declination of center of image          
TRAKTIME   = 2.0000000000000000 /Exposure time used for autoguiding              
FOCALLEN   = 0.00000000000000000 /Focal length of telescope in mm                
APTDIA     = 0.00000000000000000 /Aperture diameter of telescope in mm            
APTAREA    = 0.00000000000000000 /Aperture area of telescope in mm^2              
SWCREATE   = 'MaxIm DL Version 4.61' /Name of software that created the image      
SBSTDVER   = 'SBFITSEXT Version 1.0' /Version of SBFITSEXT standard in effect      
FLIPSTAT   = '        '                                                            
SWOWNER    = 'Thomas W. Earle' /   Licensed owner of software                      
INPUTFMT   = 'FITS    ' /          Format of file from which image was read        
SWMODIFY   = 'MaxIm DL Version 4.61' /Name of software that modified the image    
HISTORY      Bias Subtraction (Bias 3, 4096 x 4096, Bin1 x 1, Temp -35C,            
HISTORY      Exp Time 0ms)                                                          
CALSTAT    = 'BDF     '                                                            
HISTORY      Dark Subtraction (Dark 18, 4096 x 4096, Bin1 x 1, Temp -35C,          
HISTORY      Exp Time 600s)                                                        
HISTORY      Flat Field (Flat FSQ (Lum) 02Apr08, 4096 x 4096, Bin1 x 1,            
HISTORY      Temp -35C, Exp Time 1s)                                                
PEDESTAL   = -100 /Correction to add for zero-based ADU            
CSTRETCH   = 'Medium  ' /          Initial display stretch mode                    
CBLACK     = 6615 /Initial display black level in ADUs            
CWHITE     = 8461 /Initial display white level in ADUs            

Here's the FITS header after using DynamicAlignment and saving the file:

SIMPLE     = T / file does conform to FITS standard            
BITPIX     = -32 / number of bits per data pixel                  
NAXIS      = 2 / number of data axes                            
NAXIS1     = 4096 / length of data axis 1                          
NAXIS2     = 4096 / length of data axis 2                          
EXTEND     = T / FITS dataset may contain extensions            
COMMENT      FITS (Flexible Image Transport System) format is defined in 'Astronomy
COMMENT      and Astrophysics', volume 376, page 359; bibcode: 2001A&A...376..359H
PINSIGHT   = 'PCL 01.00.37.0178'  / PCL: PixInsight Core Class Library            
COLORSPC   = 'Grayscale'          / PCL: Color space                              
RESOLUTN   = 72. / PCL: Resolution in pixels per resolution unit  
RESOUNIT   = 'inch    '           / PCL: Resolution unit                          
ICCPROFL   = 'ICCProfile'         / PCL: File includes ICC profile extension      
INPUTFMT   = 'FITS    ' /          Format of file from which image was read        

As you can see, all the original header has been destroyed.  Is there a setting in PixInsight to preserve this information?  I would highly recommend preserving the original data and just append PixInsight information to the header.

Thanks,

Wade

[Juan Conejero]

Hi Wade,

I would highly recommend preserving the original data and just append PixInsight information to the header.

This is in fact what happens when you open an existing FITS file and save it as a new FITS file. In this case, all (valid) original FITS keywords are always preserved.

However, when you generate a new image with DynamicAlignment, it doesn't inherit FITS keyword settings automatically from the original image. I agree with you that the original keywords should always be preserved in these cases.

Count on this problem fixed in the next version. In the meanwhile, a workaround is to assign the original keywords manually with the standard FITSHeader process:

- Ensure that the original image is the active image in PixInsight's workspace.

- Select File > FITS Header

- Drag an instance from the FITSHeader window to the registered image (the new image generated by DynamicAlignment). Optionally, you can create a process icon if you want to save the whole FITS header as a .psm file.

Thank you

[NKV]

Hi Wade,
Count on this problem fixed in the next version.

Hi Juan.
The problem not solved in 1.4.0 ver ?
Batch process erase important information in FITS Header.

Best regards,
Nikolay.

[Juan Conejero]

Hi Nikolay,

The problem not solved in 1.4.0 ver ?
Batch process erase important information in FITS Header.

Indeed. This is my fault - I just forgot to solve this problem in 1.4. Thank you for pointing it out.

Although my credibility has been certainly damaged :lol: I promise this will be fixed in 1.4.x.