Dither file creator¶
Instructions¶
After installing pyhetdex you can create a dither file for an IFU on command
line via the dither_file executable. The full list of arguments and options
is:
usage: dither_file [-h] [-o OUTFILE] [-m MODELBASES [MODELBASES ...]]
[-t {ifuid,ifuslot,specid}] [-s SHOTDIR] [-O ORDER_BY]
[-e EXTENSION] [-d DITHERPOS [DITHERPOS ...] | -f
DITHERPOS_FILE]
id fplane basenames [basenames ...]
Produce a dither file for the give id.
positional arguments:
id id of the chosen IFU
fplane The fplane file
basenames Basename(s) of the data files. The ``{dither}`` and
``{id}`` placeholders are replaced by the dither
number and the provided id. E.g., if the ``id``
argument is ``001``, the string
``file_D{dither}_{id}`` is replaced, for the first
dither, by file_D1_001. The placeholders don't have to
be present. The number of files must be either one or
as many as the number of dithers in the ``ditherpos``
file.
optional arguments:
-h, --help show this help message and exit
-o OUTFILE, --outfile OUTFILE
Name of a file to output. It accepts the same
placeholders as ``basename``, but ``{dither}`` is the
number of dithers (default: dither_{id}.txt)
-m MODELBASES [MODELBASES ...], --modelbases MODELBASES [MODELBASES ...]
Basename(s) of the model files. It accepts that same
place holders as ``basename``. The number of files
must be either one or as many as the number of dithers
in the ``ditherpos`` file. (default:
['masterflat_{id}'])
-t {ifuid,ifuslot,specid}, --id-type {ifuid,ifuslot,specid}
Type of the id (default: ifuslot)
-s SHOTDIR, --shotdir SHOTDIR
Directory of the shot. If not provided use some
sensible default value for image quality and
normalisation. WARNING: at the moment not used
(default: None)
-O ORDER_BY, --order-by ORDER_BY
If given, order the ``basenames`` files by the value
of the header keyword 'order_by' (default: None)
--use-hetpupil Use $CUREBIN/hetpupil to get the relative illumination
from the files passed via basename. The ``extension``
is used to have valid file names. (default: False)
-e EXTENSION, --extension EXTENSION
Extension appended to the base names to create valid
file names (default: _L.fits)
-d DITHERPOS [DITHERPOS ...], --ditherpos DITHERPOS [DITHERPOS ...]
Dither postions (default: [0.0, -1.27, -1.27, 0.0,
0.73, -0.73])
-f DITHERPOS_FILE, --ditherpos-file DITHERPOS_FILE
Name of the file containing the dither shifts. The
expected format is ``id x1 x2 ... xn y1 y2 ... yn``.
Normally the ``id`` is ``ifuslot``. This option
deactivate the ``ditherpos`` one (default: None)
Running:
dither_file -f vhc_config/reference_files/dither_positions.txt\
067 fplane.txt HETDEX_obs-1_D{dither}_{id}
creates a file called dither_067.txt:
# basename modelbase ditherx dithery seeing norm airmass
HETDEX_obs-1_D1_067 masterflat_067 0.000000 0.000000 1.600 1.0000 1.2200
HETDEX_obs-1_D2_067 masterflat_067 0.615000 1.065000 1.600 1.0000 1.2200
HETDEX_obs-1_D3_067 masterflat_067 1.230000 0.000000 1.600 1.0000 1.2200
The following:
dither_file -m model-1_{id}_D{dither}\
-o dither_067.txt 067 fplane.txt\
HETDEX_obs-1_{id}_D{dither}
creates the following file:
# basename modelbase ditherx dithery seeing norm airmass
HETDEX_obs-1_067_D1 model-1_067_D1 0.000000 0.000000 1.600 1.0000 1.2200
HETDEX_obs-1_067_D2 model-1_067_D2 -1.27000 0.730000 1.600 1.0000 1.2200
HETDEX_obs-1_067_D3 model-1_067_D3 -1.27000 0.730000 1.600 1.0000 1.2200
If the dither number is not in the base names but is stored in a header
keyword, it is possible to pass the list of base names to dither_file and
tell it to sort the names. To do so, you also give the name of the header
keyword containing the dither number and, if different from the default, the
extension to append to the base names to form valid file names. So, assuming
that dithers are taken sequentially, the following:
dither_file -O DITHER\
-f vhc_config/trunk/reference_files/dither_positions.txt\
067 fplane.txt\
20160410T000030_067_sci 20160410T000003_067_sci\
20160410T000017_067_sci
writes the file:
# basename modelbase ditherx dithery seeing norm airmass
20160410T000003_067_sci masterflat_067 0.000000 0.000000 1.600 1.0000 1.2200
20160410T000017_067_sci masterflat_067 0.615000 1.065000 1.600 1.0000 1.2200
20160410T000030_067_sci masterflat_067 1.230000 0.000000 1.600 1.0000 1.2200
With the --use-hetpupil switch, the default illumination model, is replaced
with one that uses the hetpupil executable from cure to estimate
the average pupil illumination and thus the normalisation. If, e.g., for the
above three files hetpupil return 0.9, 1.2 and 0.7, running:
dither_file -O DITHER --use-hetpupil\
-f vhc_config/trunk/reference_files/dither_positions.txt\
067 fplane.txt\
20160410T000030_067_sci 20160410T000003_067_sci\
20160410T000017_067_sci
will create a file with the second to last column like in the following example:
# basename modelbase ditherx dithery seeing norm airmass
20160410T000003_067_sci masterflat_067 0.000000 0.000000 1.600 1.0000 1.2200
20160410T000017_067_sci masterflat_067 0.615000 1.065000 1.600 1.3333 1.2200
20160410T000030_067_sci masterflat_067 1.230000 0.000000 1.600 0.7778 1.2200
The output of hetpupil is normalized to the value of the first file.