Fix some header keywords (CHECKSUM and DATASUM) (a7656a07) · Commits · Metis scientific pipeline / L2 pipelines

fix_fits_header.pro

0 → 100644

+12 −0

Original line number	Diff line number	Diff line
		pro fix_fits_header, filename
		fits_info, filename, n_ext = n_ext, /silent
		for ext = 0, n_ext do begin
		data = readfits(filename, header, exten_no = ext, /silent)
		for k = 0, n_elements(header) - 1 do begin
		while header[k].matches('\/ +') do begin
		header[k] = header[k].replace('/ ', '/ ')
		endwhile
		endfor
		modfits, filename, 0, header, exten_no = ext
		endfor
		end
		No newline at end of file

metis_l2_prep_uv.pro

+246 −241

Original line number	Diff line number	Diff line
		pro metis_l2_prep_uv

		; keyword defining if the detector reference frame must be used for the output

		ref_detector = 0
		@@ -199,7 +198,7 @@ pro metis_l2_prep_uv
		fxaddpar, primary_header, 'HISTORY', 'L2 FITS file created on ' + date

		if not ref_detector then data = metis_rectify(data, 'UV')
		fits_add_checksum, primary_header, data
		fits_add_checksum, primary_header, float(data)
		mwrfits, float(data), out_file_name, primary_header, /no_comment, /create, /silent

		journal, 'Fits file created:'
		@@ -216,6 +215,7 @@ pro metis_l2_prep_uv
		sxdelpar, base_header, 'HISTORY'

		extension_header = base_header
		fxaddpar, extension_header, 'XTENSION', 'IMAGE', 'image extension', before = 'BITPIX'
		fxaddpar, extension_header, 'PCOUNT', 0, 'parameter count', before = 'LONGSTRN'
		fxaddpar, extension_header, 'GCOUNT', 1, 'group count', before = 'LONGSTRN'
		fxaddpar, extension_header, 'EXTNAME', 'Quality matrix', 'extension name', before = 'LONGSTRN'
		@@ -228,7 +228,7 @@ pro metis_l2_prep_uv
		fxaddpar, extension_header, 'COMMENT', ' 0 = unreliable pixel value'
		fxaddpar, extension_header, 'COMMENT', ' 1 = good pixel'
		if not ref_detector then quality_matrix = metis_rectify(quality_matrix, 'UV')
		fits_add_checksum, extension_header, quality_matrix
		fits_add_checksum, extension_header, float(quality_matrix)
		mwrfits, float(quality_matrix), out_file_name, extension_header, /no_comment, /silent

		journal, 'Quality-matrix extension correctly added.'
		@@ -238,6 +238,7 @@ pro metis_l2_prep_uv
		if not ref_detector then error = metis_rectify(error, 'UV')
		error_matrix = data * sqrt(error)
		extension_header = base_header
		fxaddpar, extension_header, 'XTENSION', 'IMAGE', 'image extension', before = 'BITPIX'
		fxaddpar, extension_header, 'PCOUNT', 0, 'parameter count', before = 'LONGSTRN'
		fxaddpar, extension_header, 'GCOUNT', 1, 'group count', before = 'LONGSTRN'
		fxaddpar, extension_header, 'EXTNAME', 'Error matrix', 'extension name', before = 'LONGSTRN'
		@@ -250,6 +251,10 @@ pro metis_l2_prep_uv

		journal, 'Error-matrix extension correctly added.'

		; fix some header keywords

		fix_fits_header, out_file_name

		; write the auxiliary information file

		output = { $

metis_l2_prep_vl_generic.pro

+292 −287

Original line number	Diff line number	Diff line
		pro metis_l2_prep_vl_generic

		; keyword defining if the detector reference frame must be used for the output

		ref_detector = 0
		@@ -193,16 +192,16 @@ pro metis_l2_prep_vl_generic
		if header.pol_id ne 5 then begin
		if fix(header.hdr_vers) le 4 then begin
		case header.pol_id of
		0: dacpol = header.dac1pol1
		1: dacpol = header.dac1pol1
		2: dacpol = header.dac1pol2
		3: dacpol = header.dac1pol3
		4: dacpol = header.dac1pol4
		0: dacpol = header.dac1Pol1
		1: dacpol = header.dac1Pol1
		2: dacpol = header.dac1Pol2
		3: dacpol = header.dac1Pol3
		4: dacpol = header.dac1Pol4
		endcase
		endif

		if fix(header.hdr_vers) ge 5 then begin
		dacpol = header.dac1pol1
		dacpol = header.dac1Pol1
		endif

		k = where(dacpol_cal.dacpol eq dacpol)
		@@ -236,7 +235,7 @@ pro metis_l2_prep_vl_generic
		; add checksum and datasum to the fits header

		if not ref_detector then data = metis_rectify(data, 'VL')
		fits_add_checksum, primary_header, data
		fits_add_checksum, primary_header, float(data)
		mwrfits, float(data), out_file_name, primary_header, /no_comment, /create, /silent

		journal, 'Fits file created:'
		@@ -253,6 +252,7 @@ pro metis_l2_prep_vl_generic
		sxdelpar, base_header, 'HISTORY'

		extension_header = base_header
		fxaddpar, extension_header, 'XTENSION', 'IMAGE', 'image extension', before = 'BITPIX'
		fxaddpar, extension_header, 'PCOUNT', 0, 'parameter count', before = 'LONGSTRN'
		fxaddpar, extension_header, 'GCOUNT', 1, 'group count', before = 'LONGSTRN'
		fxaddpar, extension_header, 'EXTNAME', 'Quality matrix', 'extension name', before = 'LONGSTRN'
		@@ -265,7 +265,7 @@ pro metis_l2_prep_vl_generic
		fxaddpar, extension_header, 'COMMENT', ' 0 = unreliable pixel value'
		fxaddpar, extension_header, 'COMMENT', ' 1 = good pixel'
		if not ref_detector then quality_matrix = metis_rectify(quality_matrix, 'VL')
		fits_add_checksum, extension_header, quality_matrix
		fits_add_checksum, extension_header, float(quality_matrix)
		mwrfits, float(quality_matrix), out_file_name, extension_header, /no_comment, /silent

		journal, 'Quality-matrix extension correctly added.'
		@@ -275,6 +275,7 @@ pro metis_l2_prep_vl_generic
		if not ref_detector then error = metis_rectify(error, 'VL')
		error_matrix = data * sqrt(error)
		extension_header = base_header
		fxaddpar, extension_header, 'XTENSION', 'IMAGE', 'image extension', before = 'BITPIX'
		fxaddpar, extension_header, 'PCOUNT', 0, 'parameter count', before = 'LONGSTRN'
		fxaddpar, extension_header, 'GCOUNT', 1, 'group count', before = 'LONGSTRN'
		fxaddpar, extension_header, 'EXTNAME', 'Error matrix', 'extension name', before = 'LONGSTRN'
		@@ -286,6 +287,10 @@ pro metis_l2_prep_vl_generic

		journal, 'Error-matrix extension correctly added.'

		; fix some header keywords

		fix_fits_header, out_file_name

		; write the auxiliary information file

		output = { $

metis_l2_prep_vl_polariz.pro

+773 −763

Original line number	Diff line number	Diff line
		pro metis_l2_prep_vl_polariz

		; keyword defining if the detector reference frame must be used for the output

		ref_detector = 0
		@@ -51,7 +50,6 @@ pro metis_l2_prep_vl_polariz
		quality_matrix = 1.

		for k = 0, 3 do begin

		; read the input image

		image = mrdfits(input.file_name[k], 0, primary_header, /silent)
		@@ -100,10 +98,10 @@ pro metis_l2_prep_vl_polariz
		; check consistency of pmp raw voltages (dacpol)

		if $
		header.dac1pol1 ne header.dac2pol1 or $
		header.dac1pol2 ne header.dac2pol2 or $
		header.dac1pol3 ne header.dac2pol3 or $
		header.dac1pol4 ne header.dac2pol4 then begin
		header.dac1Pol1 ne header.dac2Pol1 or $
		header.dac1Pol2 ne header.dac2Pol2 or $
		header.dac1Pol3 ne header.dac2Pol3 or $
		header.dac1Pol4 ne header.dac2Pol4 then begin
		journal, 'Error 05: image has inconsistent PMP voltages.'
		journal
		exit, status = 5
		@@ -193,26 +191,24 @@ pro metis_l2_prep_vl_polariz
		stokes_subdark = dblarr(header.naxis1, header.naxis2, 3)
		stokes_abs_error = dblarr(header.naxis1, header.naxis2, 3)
		for i = 0, 2 do begin

		journal, ' stokes = ' + stokes_name[i]

		for j = 0, 3 do begin

		journal, ' pol_id = ' + string(data_header[j].pol_id, format = '(I0)')

		; check the polarization state of the image and select the corresponding dacpol value

		if fix(data_header[j].hdr_vers) le 4 then begin
		case data_header[j].pol_id of
		1: dacpol = data_header[j].dac1pol1
		2: dacpol = data_header[j].dac1pol2
		3: dacpol = data_header[j].dac1pol3
		4: dacpol = data_header[j].dac1pol4
		1: dacpol = data_header[j].dac1Pol1
		2: dacpol = data_header[j].dac1Pol2
		3: dacpol = data_header[j].dac1Pol3
		4: dacpol = data_header[j].dac1Pol4
		endcase
		endif

		if fix(data_header[j].hdr_vers) ge 5 then begin
		dacpol = data_header[j].dac1pol1
		dacpol = data_header[j].dac1Pol1
		endif

		; select the correct demodulation tensor element based on effective angle and stokes paramater
		@@ -312,8 +308,8 @@ pro metis_l2_prep_vl_polariz

		; compute the polarization angle from the stokes q and u

		pol_angle = 0.5D0 * atan(stokes[, , 2], stokes[, , 1])
		pol_angle_error = (q^2 * u_abs_error^2 + u^2 * q_abs_error^2)/(2D0 * pb_image^4)/pol_angle^2
		pol_angle = 0.5d0 * atan(stokes[, , 2], stokes[, , 1])
		pol_angle_error = (q ^ 2 * u_abs_error ^ 2 + u ^ 2 * q_abs_error ^ 2) / (2d0 * pb_image ^ 4) / pol_angle ^ 2

		pol_angle = pol_angle * !radeg

		@@ -436,7 +432,7 @@ pro metis_l2_prep_vl_polariz
		; add checksum and datasum to the fits header

		if not ref_detector then pb_image = metis_rectify(pb_image, 'VL')
		fits_add_checksum, primary_pb_header, pb_image
		fits_add_checksum, primary_pb_header, float(pb_image)
		mwrfits, float(pb_image), out_file_name[0], primary_pb_header, /no_comment, /create, /silent

		journal, 'Polarized-brightness FITS file created:'
		@@ -453,6 +449,7 @@ pro metis_l2_prep_vl_polariz
		sxdelpar, base_header, 'HISTORY'

		extension_header = base_header
		fxaddpar, extension_header, 'XTENSION', 'IMAGE', 'image extension', before = 'BITPIX'
		fxaddpar, extension_header, 'PCOUNT', 0, 'parameter count', before = 'LONGSTRN'
		fxaddpar, extension_header, 'GCOUNT', 1, 'group count', before = 'LONGSTRN'
		fxaddpar, extension_header, 'EXTNAME', 'Quality matrix', 'extension name', before = 'LONGSTRN'
		@@ -465,7 +462,7 @@ pro metis_l2_prep_vl_polariz
		fxaddpar, extension_header, 'COMMENT', ' 0 = unreliable pixel value'
		fxaddpar, extension_header, 'COMMENT', ' 1 = good pixel'
		if not ref_detector then pb_quality_matrix = metis_rectify(pb_quality_matrix, 'VL')
		fits_add_checksum, extension_header, pb_quality_matrix
		fits_add_checksum, extension_header, float(pb_quality_matrix)
		mwrfits, float(pb_quality_matrix), out_file_name[0], extension_header, /no_comment, /silent

		journal, 'Quality-matrix extension correctly added.'
		@@ -475,17 +472,22 @@ pro metis_l2_prep_vl_polariz
		if not ref_detector then pb_error = metis_rectify(pb_error, 'VL')
		error_matrix = pb_image * 0. ; pb_image * sqrt(pb_error)
		extension_header = base_header
		fxaddpar, extension_header, 'XTENSION', 'IMAGE', 'image extension', before = 'BITPIX'
		fxaddpar, extension_header, 'PCOUNT', 0, 'parameter count', before = 'LONGSTRN'
		fxaddpar, extension_header, 'GCOUNT', 1, 'group count', before = 'LONGSTRN'
		fxaddpar, extension_header, 'EXTNAME', 'Error matrix', 'extension name', before = 'LONGSTRN'
		fxaddpar, extension_header, 'BTYPE', 'Absolute error'
		fxaddpar, extension_header, 'DATAMIN', min(error_matrix, /nan)
		fxaddpar, extension_header, 'DATAMAX', max(error_matrix, /nan)
		fits_add_checksum, extension_header, error_matrix
		fits_add_checksum, extension_header, float(error_matrix)
		mwrfits, float(error_matrix), out_file_name[0], extension_header, /no_comment, /silent

		journal, 'Error-matrix extension correctly added.'

		; fix some header keywords

		fix_fits_header, out_file_name[0]

		; keywords specific for total brightness images

		primary_tb_header = primary_header
		@@ -509,7 +511,7 @@ pro metis_l2_prep_vl_polariz
		; add checksum and datasum to the fits header

		if not ref_detector then tb_image = metis_rectify(tb_image, 'VL')
		fits_add_checksum, primary_tb_header, tb_image
		fits_add_checksum, primary_tb_header, float(tb_image)
		mwrfits, float(tb_image), out_file_name[1], primary_tb_header, /no_comment, /create, /silent

		journal, 'Total-brightness FITS file created:'
		@@ -526,6 +528,7 @@ pro metis_l2_prep_vl_polariz
		sxdelpar, base_header, 'HISTORY'

		extension_header = base_header
		fxaddpar, extension_header, 'XTENSION', 'IMAGE', 'image extension', before = 'BITPIX'
		fxaddpar, extension_header, 'PCOUNT', 0, 'parameter count', before = 'LONGSTRN'
		fxaddpar, extension_header, 'GCOUNT', 1, 'group count', before = 'LONGSTRN'
		fxaddpar, extension_header, 'EXTNAME', 'Quality matrix', 'extension name', before = 'LONGSTRN'
		@@ -538,7 +541,7 @@ pro metis_l2_prep_vl_polariz
		fxaddpar, extension_header, 'COMMENT', ' 0 = unreliable pixel value'
		fxaddpar, extension_header, 'COMMENT', ' 1 = good pixel'
		if not ref_detector then tb_quality_matrix = metis_rectify(tb_quality_matrix, 'VL')
		fits_add_checksum, extension_header, tb_quality_matrix
		fits_add_checksum, extension_header, float(tb_quality_matrix)
		mwrfits, float(tb_quality_matrix), out_file_name[1], extension_header, /no_comment, /silent

		journal, 'Quality-matrix extension correctly added.'
		@@ -548,17 +551,22 @@ pro metis_l2_prep_vl_polariz
		if not ref_detector then tb_error = metis_rectify(tb_error, 'VL')
		error_matrix = tb_image * 0. ; tb_image * sqrt(tb_error)
		extension_header = base_header
		fxaddpar, extension_header, 'XTENSION', 'IMAGE', 'image extension', before = 'BITPIX'
		fxaddpar, extension_header, 'PCOUNT', 0, 'parameter count', before = 'LONGSTRN'
		fxaddpar, extension_header, 'GCOUNT', 1, 'group count', before = 'LONGSTRN'
		fxaddpar, extension_header, 'EXTNAME', 'Error matrix', 'extension name', before = 'LONGSTRN'
		fxaddpar, extension_header, 'BTYPE', 'Absolute error'
		fxaddpar, extension_header, 'DATAMIN', min(error_matrix, /nan)
		fxaddpar, extension_header, 'DATAMAX', max(error_matrix, /nan)
		fits_add_checksum, extension_header, error_matrix
		fits_add_checksum, extension_header, float(error_matrix)
		mwrfits, float(error_matrix), out_file_name[1], extension_header, /no_comment, /silent

		journal, 'Error-matrix extension correctly added.'

		; fix some header keywords

		fix_fits_header, out_file_name[1]

		; keywords specific for polarization-angle images

		primary_polangle_header = primary_header
		@@ -582,7 +590,7 @@ pro metis_l2_prep_vl_polariz
		; add checksum and datasum to the fits header

		if not ref_detector then pol_angle = metis_rectify(pol_angle, 'VL')
		fits_add_checksum, primary_polangle_header, pol_angle
		fits_add_checksum, primary_polangle_header, float(pol_angle)
		mwrfits, float(pol_angle), out_file_name[2], primary_polangle_header, /no_comment, /create, /silent

		journal, 'Polarization-angle FITS file created:'
		@@ -599,6 +607,7 @@ pro metis_l2_prep_vl_polariz
		sxdelpar, base_header, 'HISTORY'

		extension_header = base_header
		fxaddpar, extension_header, 'XTENSION', 'IMAGE', 'image extension', before = 'BITPIX'
		fxaddpar, extension_header, 'PCOUNT', 0, 'parameter count', before = 'LONGSTRN'
		fxaddpar, extension_header, 'GCOUNT', 1, 'group count', before = 'LONGSTRN'
		fxaddpar, extension_header, 'EXTNAME', 'Quality matrix', 'extension name', before = 'LONGSTRN'
		@@ -611,7 +620,7 @@ pro metis_l2_prep_vl_polariz
		fxaddpar, extension_header, 'COMMENT', ' 0 = unreliable pixel value'
		fxaddpar, extension_header, 'COMMENT', ' 1 = good pixel'
		if not ref_detector then pol_angle_quality_matrix = metis_rectify(quality_matrix, 'VL')
		fits_add_checksum, extension_header, pol_angle_quality_matrix
		fits_add_checksum, extension_header, float(pol_angle_quality_matrix)
		mwrfits, float(pol_angle_quality_matrix), out_file_name[2], extension_header, /no_comment, /silent

		journal, 'Quality-matrix extension correctly added.'
		@@ -621,17 +630,22 @@ pro metis_l2_prep_vl_polariz
		if not ref_detector then pol_angle_error = metis_rectify(pol_angle_error, 'VL')
		error_matrix = pol_angle * 0. ; pol_angle * sqrt(pol_angle_error)
		extension_header = base_header
		fxaddpar, extension_header, 'XTENSION', 'IMAGE', 'image extension', before = 'BITPIX'
		fxaddpar, extension_header, 'PCOUNT', 0, 'parameter count', before = 'LONGSTRN'
		fxaddpar, extension_header, 'GCOUNT', 1, 'group count', before = 'LONGSTRN'
		fxaddpar, extension_header, 'EXTNAME', 'Error matrix', 'extension name', before = 'LONGSTRN'
		fxaddpar, extension_header, 'BTYPE', 'Absolute error'
		fxaddpar, extension_header, 'DATAMIN', min(error_matrix, /nan)
		fxaddpar, extension_header, 'DATAMAX', max(error_matrix, /nan)
		fits_add_checksum, extension_header, error_matrix
		fits_add_checksum, extension_header, float(error_matrix)
		mwrfits, float(error_matrix), out_file_name[2], extension_header, /no_comment, /silent

		journal, 'Error-matrix extension correctly added.'

		; fix some header keywords

		fix_fits_header, out_file_name[2]

		; management of stokes images

		journal, 'Calibrating Stokes parameter I...'
		@@ -677,7 +691,7 @@ pro metis_l2_prep_vl_polariz

		; add checksum and datasum to the fits header
		if not ref_detector then i = metis_rectify(i, 'VL')
		fits_add_checksum, primary_stokes_header, i
		fits_add_checksum, primary_stokes_header, float(i)
		mwrfits, float(i), out_file_name[3], primary_stokes_header, /no_comment, /create, /silent

		journal, 'Stokes parameters FITS file created:'
		@@ -685,14 +699,14 @@ pro metis_l2_prep_vl_polariz

		; add the extension with the stokes q image

		extension_header = primary_stokes_header
		sxdelpar, extension_header, 'SIMPLE'
		sxdelpar, extension_header, 'EXTEND'
		sxdelpar, extension_header, 'DATASUM'
		sxdelpar, extension_header, 'CHECKSUM'
		sxdelpar, extension_header, 'COMMENT'
		sxdelpar, extension_header, 'HISTORY'
		base_header = primary_stokes_header
		sxdelpar, base_header, 'SIMPLE'
		sxdelpar, base_header, 'EXTEND'
		sxdelpar, base_header, 'DATASUM'
		sxdelpar, base_header, 'CHECKSUM'

		extension_header = base_header
		fxaddpar, extension_header, 'XTENSION', 'IMAGE', 'image extension', before = 'BITPIX'
		fxaddpar, extension_header, 'PCOUNT', 0, 'parameter count', before = 'LONGSTRN'
		fxaddpar, extension_header, 'GCOUNT', 1, 'group count', before = 'LONGSTRN'
		fxaddpar, extension_header, 'EXTNAME', 'Stokes Q', 'extension name', before = 'LONGSTRN'
		@@ -702,21 +716,15 @@ pro metis_l2_prep_vl_polariz
		fxaddpar, extension_header, 'DATAMAX', max(q, /nan)
		sxdelpar, extension_header, 'EXTEND'
		if not ref_detector then q = metis_rectify(q, 'VL')
		fits_add_checksum, extension_header, q
		fits_add_checksum, extension_header, float(q)
		mwrfits, float(q), out_file_name[3], extension_header, /no_comment, /silent

		journal, 'Q parameter extension correctly added.'

		; add the extension with the stokes u image

		extension_header = primary_stokes_header
		sxdelpar, extension_header, 'SIMPLE'
		sxdelpar, extension_header, 'EXTEND'
		sxdelpar, extension_header, 'DATASUM'
		sxdelpar, extension_header, 'CHECKSUM'
		sxdelpar, extension_header, 'COMMENT'
		sxdelpar, extension_header, 'HISTORY'

		extension_header = base_header
		fxaddpar, extension_header, 'XTENSION', 'IMAGE', 'image extension', before = 'BITPIX'
		fxaddpar, extension_header, 'PCOUNT', 0, 'parameter count', before = 'LONGSTRN'
		fxaddpar, extension_header, 'GCOUNT', 1, 'group count', before = 'LONGSTRN'
		fxaddpar, extension_header, 'EXTNAME', 'Stokes U', 'extension name', before = 'LONGSTRN'
		@@ -726,21 +734,18 @@ pro metis_l2_prep_vl_polariz
		fxaddpar, extension_header, 'DATAMAX', max(u, /nan)
		sxdelpar, extension_header, 'EXTEND'
		if not ref_detector then u = metis_rectify(u, 'VL')
		fits_add_checksum, extension_header, u
		fits_add_checksum, extension_header, float(u)
		mwrfits, float(u), out_file_name[3], extension_header, /no_comment, /silent

		journal, 'U parameter extension correctly added.'

		; add the extension with the quality matrix

		base_header = primary_stokes_header
		sxdelpar, base_header, 'EXTEND'
		sxdelpar, base_header, 'DATASUM'
		sxdelpar, base_header, 'CHECKSUM'
		sxdelpar, base_header, 'COMMENT'
		sxdelpar, base_header, 'HISTORY'

		; add the extension with the quality matrix

		extension_header = base_header
		fxaddpar, extension_header, 'XTENSION', 'IMAGE', 'image extension', before = 'BITPIX'
		fxaddpar, extension_header, 'PCOUNT', 0, 'parameter count', before = 'LONGSTRN'
		fxaddpar, extension_header, 'GCOUNT', 1, 'group count', before = 'LONGSTRN'
		fxaddpar, extension_header, 'EXTNAME', 'Quality matrix', 'extension name', before = 'LONGSTRN'
		@@ -753,7 +758,7 @@ pro metis_l2_prep_vl_polariz
		fxaddpar, extension_header, 'COMMENT', ' 0 = unreliable pixel value'
		fxaddpar, extension_header, 'COMMENT', ' 1 = good pixel'
		if not ref_detector then quality_matrix = metis_rectify(quality_matrix, 'VL')
		fits_add_checksum, extension_header, quality_matrix
		fits_add_checksum, extension_header, float(quality_matrix)
		mwrfits, float(quality_matrix), out_file_name[3], extension_header, /no_comment, /silent

		journal, 'Quality-matrix extension correctly added.'
		@@ -763,17 +768,22 @@ pro metis_l2_prep_vl_polariz
		if not ref_detector then error_matrix = metis_rectify(error_matrix, 'VL')
		error_matrix = tb_image * 0. ; tb_image * sqrt(tb_error)
		extension_header = base_header
		fxaddpar, extension_header, 'XTENSION', 'IMAGE', 'image extension', before = 'BITPIX'
		fxaddpar, extension_header, 'PCOUNT', 0, 'parameter count', before = 'LONGSTRN'
		fxaddpar, extension_header, 'GCOUNT', 1, 'group count', before = 'LONGSTRN'
		fxaddpar, extension_header, 'EXTNAME', 'Error matrix', 'extension name', before = 'LONGSTRN'
		fxaddpar, extension_header, 'BTYPE', 'Absolute error'
		fxaddpar, extension_header, 'DATAMIN', min(error_matrix, /nan)
		fxaddpar, extension_header, 'DATAMAX', max(error_matrix, /nan)
		fits_add_checksum, extension_header, error_matrix
		fits_add_checksum, extension_header, float(error_matrix)
		mwrfits, float(error_matrix), out_file_name[3], extension_header, /no_comment, /silent

		journal, 'Error-matrix extension correctly added.'

		; fix some header keywords

		fix_fits_header, out_file_name[3]

		; write the auxiliary information file

		output = { $