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Nearly all of the infomation contained in the headers of the spSlit files
is carried through the pipeline and is present in the headers of subsequent
slit and spec1d files. To access the header of a spSlit file, use the
GODDARD routine headfits as follows IDL> hdr = headfits('spSlit.2200.004B.fits', ext=1) which reads the header corresponding to the 1st extension in the file. Another GODDARD routine, hprint is very useful for viewing the header. The syntax for this command goes like IDL> hprint, hdr Executing this command will display the header info in an easily read 3 column format. The first column gives the header keyword name, column two displays the value corresponding to that keyword, and the third column (preceeded by the slash) is a comment field providing additional information regarding the keyword. To access a header field, use the GODDARD routine sxpar as in this example: IDL> maskname = sxpar(hdr, 'SLMSKNAM') IDL> hprint, hdr XTENSION= 'BINTABLE' /Written by IDL: Fri Apr 11 23:13:50 2003 BITPIX = 8 / NAXIS = 2 /Binary table NAXIS1 = 15323982 /Number of bytes per row NAXIS2 = 1 /Number of rows PCOUNT = 0 /Random parameter count GCOUNT = 1 /Group count TFIELDS = 10 /Number of columns COMMENT COMMENT *** End of mandatory fields *** COMMENT EXTNAME = 'spSlit ' /Extension name DATE = '2003-04-12' /Creation date FRAMENO = 8 / OUTFILE = 'd0813_ ' / EXPTIME = 1199.89562988 /exposure time in seconds of corresponding science frame DARKTIME= 1350.89843750 / OBSERVER= 'Faber, Coil, Schiavon, Wirth @ HQ' / OBJECT = '2200.E; spectral' / OBSTYPE = 'Object ' / ROTATVAL= -28.4648799900 / DATE-OBS= '2002-08-13' /date yyyy-mm-dd of observation UT = 0 / AIRMASS = 1.03829658000 / TARGNAME= '2200.E ' / EQUINOX = 2000.00000000 / DEC = '+34:50:17.8' / RA = '16:49:57.52' / AZ = -16.2377247700 / EL = 74.3740611200 / HA = '+00:21:23.00' / ST = '17:11:26.25' / UTC = '06:07:25.92' / MJD-OBS = '52499.255075' / PARANG = 161.153934030 / SYNOPSIS= '1200 s, Object Spectral 2200.E/1200G/OG550 Off' / DWFILNAM= 'OG550 ' / SLMSKNAM= '2200.E ' /slitmask name GRATEPOS= 3 /grating position: slider 3 or 4 HPLOGTIM= 'Mon Aug 12 20:21:16 HST 2002' / SP2DVERS= 'v1_1_1 ' /Version of spec2d AUTHOR = 'Finkbeiner & Davis' / CHIPNO = 1 /chip number for this slitlet SLITNO = 1 /slit number SLITX0 = 650.268 /center of trace SLITX1 = 1023.67 /center of trace SHIFT0 = 0.674259 /shift to fix low-x slit end SHIFT1 = 0.242833 /shift to fix high-x slit end COMMENT COMMENT *** Column names *** COMMENT TTYPE1 = 'FLUX ' / TTYPE2 = 'IVAR ' / TTYPE3 = 'LAMBDAX ' / TTYPE4 = 'TILTX ' / TTYPE5 = 'MASK ' / TTYPE6 = 'SLITFN ' / TTYPE7 = 'SKYROW ' / TTYPE8 = 'SLITWIDTH ' / TTYPE9 = 'DLAM ' / TTYPE10 = 'INFOMASK ' / COMMENT COMMENT *** Column formats *** COMMENT TFORM1 = '1531904E' / TFORM2 = '1531904E' / TFORM3 = '6D ' / TFORM4 = '3D ' / TFORM5 = '1531904B' / TFORM6 = '374D ' / TFORM7 = '374B ' / TFORM8 = 'D ' / TFORM9 = '374E ' / TFORM10 = '1531904B' / COMMENT COMMENT *** Column dimensions (2 D or greater) *** COMMENT TDIM1 = '( 4096, 374)' / TDIM2 = '( 4096, 374)' / TDIM5 = '( 4096, 374)' / TDIM10 = '( 4096, 374)' / COMMENT FLUX array in units of counts/hour SLITPA = 27.5000 /Slit PA on sky MASKPA = 27.5000 /Mask PA on sky SKYSIGMA= 0.662672 /Gaussian sigma of skylines (AA) WAVETYPE= 'POLYFLAG' /wavelength solution method END IDL> The comments in red font are not set by the pipeline and have been added in this documentation to aid the user. |