nflinearize: Linearize NEWFIRM exposures

Package: newfirm

Usage

nflinearize input output

Parameters

input: List of input NEWFIRM MEF files. Files which have already been linearized are silently skipped.

output: List, pattern, or expression defining output filenames for each input file. See proctool.output for a description of the various options.

coeffs = "parameter" (parameter|exprdb|keyword|image): Coefficients

lin1, lin2, lin3, lin4

Linearity coefficients for each NEWFIRM extension. These parameters are only used when the coeffs parameter is "parameter". This allows easy user control. The default values are

lin1 = -5.404E-6
lin2 = -5.952E-6
lin3 = -6.123E-6
lin4 = -7.037E-6

which were recommended in Nov. 2008.

linimage = "": List of linearity coefficient images. The images must be the same size as the NEWFIRM arrays and pixels are matched by pixel coordinates. The pixel values are the coefficient values for the linearization expression. The list need not match the input list and the last coefficient image is used for longer input lists while extra coefficient images in the list are not used. The typical usage would be a single MEF or one image for each extension. The images are matched to the input by the IMAGEID keyword. This parameter is only used with coeffs is "image".

exprdb = "newfirm$exprdb.dat": Expression database. This file is critical to the linearization operation because it defines the linearization expression used by this task. It also contains many of the instrument parameters and recommended coefficients for NEWFIRM. This file may be updated independently of this task if new linearization expressions and coefficients are recommended. Users may copy the default file to their own directory, make modifications and reset this parameter.

list = no: Verbose list output only? This maps to the "vlist" output type described in proctool.output.

logfiles = "STDOUT": List of log files for log output. The special value "STDOUT" may be used to write to the terminal. The output is appending to any existing output. This is described further in proctool.output.

Description

This task applies a linearization expression to each input pixel to correct from measured counts to linear counts. This task is based on the more general, and hence complex, task nfproc. It simplifies the parameters and generates the recommended linearization expressions.

Expressions

coeffs = "parameter": %(lin(nflinearize.lin\I))

coeffs = "exprdb": %(lin(L\I))

coeffs = "keyword": %(lin(lincoeff))

coeffs = "image": %(lin($L))

The "lin" macro is defined in the expression database. That macro is further expanded by other macros. The example below shows the final expression that is actually executed.

Nfproc

This task simply formats the linearity expression and hides and fixes most of the parameters for nfproc. The command that is executed is

nfproc (input, output, outtype=outtype, logfiles=logfiles,
    trim=no, fixpix=no, biascor=no, lincor=yes, permask=no,
    darkcor=no, flatcor=no, skysub=no, replace=no, normalize=no,
    dorder="TXBD", forder="TXBDLR,N", order="TXBDLFR,S",
    bpm="(bpm)", obm="(objmask)", trimsec="(trimsec)",
    biassec="(biassec)", linexpr=expr, linimage=linimage,
    persist="", perwindow="5", darks="", flats="", flatexpr="",
    skies="", skymatch="", skymode="median 10", repexpr="",
    repimage="", btype="fit", bfunction="legendre",
    bsample="*", border="1", bnaverage="1", bniterate="1",
    bhreject="3.", blreject="3.", bgrow="0.", intype="",
    dtype="(obstype='dark')", ftype="(obstype='flat')",
    gtype="", stype="", imageid="(str(imageid))",
    filter="(filter)", sortval="(@'mjd-obs')", exptime="(exptime)",
    opdb="newfirm$opdb.dat", exprdb=exprdb, override=no, copy=no,
    erraction="warn", gdevice="stdgraph", gcursor="", gplotfile="")

where "expr" is the expression created by this task.

References

Dickinson, M. 2008, NEWFIRM Linearity Calibration,