Name
spjitter - ISAAC (SW and LW) jitter spectroscopic reduction
Synopsis
spjitter [flags] [options]
Description
spjitter reduces images taken in jitter spectroscopic mode. It has a
list of several possible algorithms with associated parameters for each
reduction stage.
spjitter has been developped to reduce jitter spectroscopic data taken
from ISAAC in both chopping and non-chopping modes with both SW or LW
arms. Although some features are specific to this instrument, the
same algorithms should work on similar data.
spjitter is configured through an initialization file. The name of this
file is defaulted to spjitter.ini but can be changed through the use
of the -f option. In thefollowing documentation, this file is referred
to as the ini file.
Process
The reduction process is composed by files classification, correction
of the distortion, re-centering of the frames, flatfield correction,
averaging, wavelength calibration, frames combination, detection,
extraction of a spectrum. Describing all the algorithms in this command
is far beyond the scope of this manual page.
A documentation about the spjitter algorithm is in progress at the
moment.
To setup the process, you need first to generate a default spjitter.ini
file and then change parameters according to your needs. This initial-
ization file is self-documented.
Flags
Flags which can be activated on the command-line are the following:
-t or --time
Activate time estimation tools. This actually triggers a clock
when the process is running and produces duration estimations in
CPU and user time at the end.
Options
-c or --calib calib.ascii
This option can only be used together with the -g option. It
will generate a default ini file where the names of the calibra-
tion files are deduced from the contents of the provided
’calib.ascii’ file. This file should contain two columns: the
first one gives the name of the calibration file, the second one
specifies its type.
-f or --file filename
Changes the name of the ini file from spjitter.ini to filename.
-g or --generate
Generates a default ini file in the current directory, and a
default empty frame list called framelist.ascii. You can fill
up the ASCII list of input names by using the ls command:
ls -1 *.fits >> framelist.ascii
or:
dfits *.fits | fitsort DPR.TYPE >> framelist.ascii
Of course, the list of frames need not be named
’framelist.ascii’, this is the default name only. Change it if
you wish in the ini file.
-A or --algorithm algo
is used together with the -g option to generate an ini file with
the defaults set for the specified instrument. Possible values
for algo are chop, nochop or auto.
-w or --gui
Launches a GUI to use spjitter
-h or --help
Displays a short reminder of possible options and flags.
-i or --in filename
This option can only be used together with the -g option. It
will generate a default ini file where the name of the input
framelist is not the default but the one provided to this
option.
-o or --out basename
This option can only be used together with the -g option. It
will generate a default ini file where the output basename is
not the default but the one provided to this option.
Files
The ini file which is generated by using the -g option is self-docu-
mented, all parameters are described in the file comments.
The ini file consists of [Sections] followed by
keyword = value lines.
Section names and keywords are case-insensitive. Values associated to
keuwords may be integer, floating point numbers, character strings, or
flags. Types associated to keywords are usually indicated in the com-
ment section. Character strings as keyword values are case-sensitive.
Flags are given as Yes/Y/yes or No/N/no.
Comments in the ini file are identified by lines starting with a hash
(#) sign, and generally everything after a semicolon (;) and before the
end of the line. The semicolon is not mandatory, the two 5A following
lines are strictly equivalent:
ExposureTime = 1000 ; integer value in seconds
ExposureTime = 1000
It is advised to use the -A option when the ini file is generated.