====== simpix ====== :Summary: simpix files contain the noiseless CCD pixel image. The corresponding pix-\*.fits files contain the noisy realization of this image like the real data would see. It optionally contains the x and y trace locations vs. wavelength. :Naming Convention: ``simpix-{CAMERA}-{EXPID}.fits``, where ``{CAMERA}`` is the spectrograph camera, *e.g.* b0, r1, z9; and ``{EXPID}`` is the 8-digit exposure ID. :Regex: ``simpix-[brz][0-9]-[0-9]{8}\.fits`` :File Type: FITS, 128 MB Contents ======== ====== ========= ===== =================== Number EXTNAME Type Contents ====== ========= ===== =================== HDU0_ ELECTRONS IMAGE Noiseless simulated image HDU1_ XCOEFF IMAGE Optional: Legendre coefficients for x vs. wavelength HDU2_ YCOEFF IMAGE Optional: Legendre coefficients for y vs. wavelength ====== ========= ===== =================== FITS Header Units ================= HDU0 ---- EXTNAME = ELECTRONS Noiseless simulated image in electrons Required Header Keywords ~~~~~~~~~~~~~~~~~~~~~~~~ .. collapse:: Required Header Keywords Table .. rst-class:: keywords ======== ============= ==== ===================== KEY Example Value Type Comment ======== ============= ==== ===================== NAXIS1 4096 int Number of pixels in y (wavelength direction) NAXIS2 4096 int Number of pixels in x (fiber direction) VSPECTER 0.0.0 str Specter version used to simulate this image ======== ============= ==== ===================== Data: FITS image [float64] HDU1 ---- EXTNAME = XCOEFF Legendre coefficients to describe the spectral trace x vs. wavelength. To evaluate, convert the wavelength in Angstroms to the domain [-1,1] using WAVEMIN and WAVEMAX, and then evaluate the Legendre polynomial:: w = 2*(wavelength - WAVEMIN) / (WAVEMAX - WAVEMIN) - 1.0 x = numpy.polynomial.legval(w, xcoeff[i]) Required Header Keywords ~~~~~~~~~~~~~~~~~~~~~~~~ Most keywords are inherited from the input PSF, which inherited them from the input Zemax spot files. .. collapse:: Required Header Keywords Table .. rst-class:: keywords ======== ================================ ===== ============================================= KEY Example Value Type Comment ======== ================================ ===== ============================================= NAXIS1 8 int Number of Legendre coefficients NAXIS2 500 int Number of spectra EXTNAME XCOEFF str DATAMIN 1.17549435082e-38 float minimum allowed data value DATAMAX 3.40282346638e+38 float maximum allowed data value DATATYPE Normalized Image str Type of image SPECTRO DESI-0224-v1.ZMX(95% are better) str ARM Blue str Spectrograph Arm ARMINT 1 int Spectrograph Arm WAVECENT 476.5 float Center Wavelength (nm) XCENT 5.379251126 float Detector X Centroid (mm) YCENT -29.956071488 float Detector Y Centroid (mm) XDIRCOS -0.0353851399911 float x direction cosine YDIRCOS -0.976475545755 float y direction cosine ZDIRCOS 4.77449053078e-312 float z direction cosine PIXSIZE 0.001 float size of pixel (mm) DIFFRACT T bool diffraction added? DETEFF T bool detector effects added? PUPIL 126.5 float Camera Pupil (mm) FOCALLEN 215.0 float Camera focal length (mm) E2VFLAG T bool e2v detector TEMP 175.0 float Detector T (K) DETSIG 5.0 float sigma for detector (um) DETTHICK 0.0 float thickness of detector (um) DATE 2013-09-12 str Date CTYPE1 X str X coordinate (mm) CTYPE2 Y str Y coordinate (mm) CRPIX1 113.0 float Reference X pixel CRPIX2 113.0 float Reference Y pixel CRVAL1 5.380413942 float Reference X value CRVAL2 -29.95920258 float Reference Y value CDELT1 0.001 float X pixel size (mm) CDELT2 0.001 float Y pixel size (mm) PSFTYPE SPOTGRID str Grid of simulated PSF spots NPIX_X 4096 int Number of CCD pixels in X direction NPIX_Y 4096 int Number of CCD pixels in Y direction NSPEC 500 int Number of spectra NWAVE 11 int Number of wavelength samples CCDPIXSZ 0.015 float CCD pixel size [mm] DFIBER 0.23 float Center-to-center pitch of fibers on slit [mm] DGROUP 0.556 float Spacing between fiber groups on slit [mm] NGROUPS 20 int Number of fiber groups per slit NFIBGRP 25 int Number of fibers per group WAVEMIN 3533 int Min wavelength for Legendre domain [-1,1] WAVEMAX 5998 int Max wavelength for Legendre domain [-1,1] WMIN_ALL 3569 int Min wavelength seen by all spectra [Ang] WMAX_ALL 5949 int Max wavelength seen by all spectra [Ang] ======== ================================ ===== ============================================= Data: FITS image [float64] HDU2 ---- EXTNAME = YCOEFF Legendre coefficients to describe the spectral trace y vs. wavelength. See the description in HDU1 for how to evaluate these. Required Header Keywords ~~~~~~~~~~~~~~~~~~~~~~~~ .. collapse:: Required Header Keywords Table .. rst-class:: keywords ======== ============= ==== ======================================== KEY Example Value Type Comment ======== ============= ==== ======================================== NAXIS1 8 int NAXIS2 500 int EXTNAME YCOEFF str WAVEMIN 3533 int Min wavelength on the CCD [Ang] WAVEMAX 5998 int Max wavelength on the CCD [Ang] WMIN_ALL 3569 int Min wavelength seen by all spectra [Ang] WMAX_ALL 5949 int Max wavelength seen by all spectra [Ang] ======== ============= ==== ======================================== Data: FITS image [float64]