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NOTE: Most of the High Level Science Products are unavailable while unscheduled maintenance is being performed. They will be incrementally restored over the course of this week. We apologize for any inconvenience.

Reading EUVE data in IRAF

Once you have obtained events and/or fits images from the EUVE search form one can read them in a few simple steps:

  • gunzip the files.

  • read the fits files with strfits (in stsdas.fitsio)

    --the euve_name_img.fits file will produce ds, sw, mw, and lw images + good times tables.
    [you can go onto spectral extraction from these files or continue and reduce the events files.]

  • running strfits on euve_name_evt.fits file will produce the equivalent of the old format data (like table0 and so on)
    tables produced will have the following names:
    adcnts.tab       lw_events.tab    orientation.tab  sw_events.tab    
    ds_events.tab    mw_events.tab    quadrant.tab     valid_times.tab 
    
    (running strfits is no longer needed with IRAF 2.11, which allows you
    to read the fits files with out converting them. And cep will run on fits events file).
    You can also read EUVE fits files with IDL. See data products for a definition of the fits extensions.

    You will need the EUVE egodata reference directory to work on event files. This is available from the software directory.


    Listed below are quick lists of EUVE IRAF reduction steps.
    Please see the software user's guide for more information.

    1. Creating a QPOE file from events file

    2. Creating time filters

    3. Extracting spectra

    4. Making a light-cruve

    5. Misc. tasks: Backmon and Detpos

    Creating a QPOE file with the Comprehensive Event Pipeline

    2. Creating time filters

    run dqselect
    eu> dqselect
    Monitor Tables (events.fit[adcnts], events.fit[quadrant],bacmon):
    edit dsadct, then LooKZen and dsq1sf
    create a time filter with gt_save and then add it to the QPOE with tfilt. eu> epar tfilt input = "gt_ds.tab" Input table name (output = "ds.qp") Output file (name = "gt_ds.tab") Name of output macro (start = "stime") Name of starting column (end = "etime") Name of ending column (cmdline = no) Command line output flag (format = ".2f") Interval format control (mode = "al")

    3. Extracting spectra

    • You have to add DISPAXS =1 header to the spectra files (see below).
      euvextract
              input = "sw.imh"        Input image
             output = "sw_e"          Output spectrum
            (center = 1020)           Spectral pixel position
           (spec_ap = "-9:9")         Spectrum aperture
          (seekspec = yes)            Find the spectral position?
           (cntr_ap = "500:1500")     Centering aperture
            (radius = 100)            Radius from center to seek
             (thres = 4)              Threshold, sigma above the noise
        (background = "average")      Background computation method
            (bkg_ap = "-100:-12,12:100") Background sample region
       (bkg_fltr_sz = 7)              Size in pixels of bkg smoothing filters
          (dispaxis = 1)              Dispersion axis
           (verbose = no)             Print informational messages?
              (mode = "al")           
       
      You can then removed contributions from higher orders, divide
      by the effective areas and exposure time with suborder
      
      eu> epar suborder
              sw_in = "2euve_j0443-037_sw"  sw input spectrum
              mw_in = "2euve_j0443-037_mw"  mw input spectrum
              lw_in = "2euve_j0443-037_lw"  lw input spectrum
             sw_out = "2euve_j0443-037_sws" sw output spectrum
             mw_out = "2euve_j0443-037_mws" mw output spectrum
             lw_out = "2euve_j0443-037_lws" lw output spectrum
            (putout = yes)            output results
          (sw_delta = 0.1)            sw delta
          (mw_delta = 0.2)            mw delta
          (lw_delta = 0.4)            lw delta
            (sw_low = 70.)            sw low range
           (sw_high = 190.)           sw high range
            (mw_low = 150.)           mw low range
           (mw_high = 350.)           mw high range
            (lw_low = 300.)           lw low range
           (lw_high = 700.)           lw high range
             (sw_mw = 170.)           sw mw join point
             (mw_lw = 340.)           mw lw join point
           (refdata = "reference/detector.tab") reference file
           (exptime = "exptime")      exposure time header card
          (graphics = "stdgraph")     graphics
              (mode = "al")           
      

    • This card was omitted from the EUVE archival format because it is specific to reduction of spectra under IRAF and, unlike the old GO products, the archival data format is not IRAF-specific.

      You can add the DISPAXIS card to an image with the standard IRAF task hedit . It will need to have the value '1', meaning the spectra run along the x-axis, as long as you haven't rotated the images.

    Misc tasks: Backmon and Detpos

    Parameters for backmon:
    eu> lpar backmon
           output = "backmon"       Name of output ST table
          (orient = "events.fit[orientation]") Name of input orientation ST table
         (refdata = "reference/detector") Name of ST table for reference data
       (detectors = "ds")           detector (for boresight quaternions)
            (skip = 1)              Number of rows to skip over
      (maxtimegap = 600)            Max gap in time (secs) for Sat. Vel. Vectors
            (time = "time")         Time column of orientation table
         (aspectw = "aspectw")      Aspect W input column name
         (aspectx = "aspectx")      Aspect X input column name
         (aspecty = "aspecty")      Aspect Y input column name
         (aspectz = "aspectz")      Aspect Z input column name
            (posx = "positionx")    Position X input column name
            (posy = "positiony")    Position Y input column name
            (posz = "positionz")    Position Z input column name
            (mode = "al")    
    
    and the new format for detpos (if you need it):
    eu>epar detpos
            input = "events.fit[orientation]" Name of input aspect ST table
           output = "detpos"        Prefix for output aspect ST tables
         (refdata = "reference/detector.tab") Name of ST table for reference data
       (detectors = "ds")           Detector list [sca|scb|scc|ds]
              (ra = RA_OBJ)       Source right ascension
             (dec = DEC_OBJ)        Source declination in decimal degrees
         (raunits = "degrees")      Units of RA [degrees|hours]
            (time = "time")         Time column of input aspect table
         (aspectw = "aspectw")      Aspect W input column name
         (aspectx = "aspectx")      Aspect X input column name
         (aspecty = "aspecty")      Aspect Y input column name
         (aspectz = "aspectz")      Aspect Z input column name
            (mode = "al")