specsky
Name
specsky– Sky Subtract 2-D spectroscopic data
Usage
specsky images outimages outpref (method) (section) (thresh)
(clobber) (logfile) (verbose)
Parameters
- images
- String. List of FITS images to prepare. Data can be provided as a
comma-separated list, or a string with a wildcard
(e.g. ‘images=S20061210*.fits’), or a foreign file containing an ascii
list of image filenames. For the ascii list option, the filename
containing the list must be provided preceded by a ‘@’ character,
e.g. 'images=@listoffiles.lis‘. The list can contain data files from
multiple SALT instruments.
- outimage
- String. A list of images. Data can be provided as a comma-separated
list, or a string with a wildcard (e.g. ‘outimages=rS20061210*.fits’), or
a foreign file containing an ascii list of image filenames. For ascii
list option, the filename containing the list must be provided
preceded by a ‘@’ character, e.g. 'outimages=@listoffiles.lis‘. This list
must be of the same size as the images argument list.
- outpref
- String. If the outpref string is non-zero in length and contains
characters other than a blank space, it will override any value of the
outimages argument. Output file names will use the name list provided
in the images argument, but adding a prefix to each output file
defined by outpref. An absolute or relative directory path can be
included in the prefix, e.g. ‘outpref=/Volumes/data/p’.
- (method)
- String. The method to use for sky subtraction. Currently, the only
option is ‘normal’ where lines will be extracted from the region
specified by section to be subtracted.
- (clobber)
- Hidden boolean. If set to ‘yes’ files contained within the outpath
directory will be overwritten by newly created files of the same
name.
- (logfile)
- String. Name of an ascii file for storing log and error messages
from the tool. The file may be new, or messages can also be appended to a
pre-existing file.
- (verbose)
- Hidden Boolean. If verbose=n, log messages will be suppressed.
Description
SPECSKY will subtract sky regions from the data. The task currently only
has one mode of operations which is ‘normal’. In this mode, the task
estimates the skylines from a region in the image specified by section. These
skylines will then be subtracted from the rest of the image.
EXAMPLES
1. To subtract sky lines with specsky:
--> specsky images='pmbxpP*.fits' outimages= outpref='r'
method='normal' section='[1200:1500]' logfile='salt.log'
Time and disk requirements
Individual unbinned raw full-frame RSS files can be 112MB in size. It is
recommended to use workstations with a minimum of 512MB RAM. On a
linux machine with 2.8 Ghz processor and 2 Gb of RAM, one 2051x2051 image
in 0.15 sec.
Bugs and limitations
The sky subtraction algorithm needs to be improved as it is very simple
and does not account for a number of effects.
Send feedback and bug reports to salthelp@saao.ac.za