1.1 HOW-TO Calibrations: overview
The calibration part of the
Astro-WISE Environment is divided into
three major
pipelines: a bias pipeline, a flat field pipeline, and a photometric
pipeline. All of these are composed of several fine-grained, atomic processing
steps known as tasks. In the following sections, these pipelines are discussed.
A summary is given of the atomic tasks that make up the various pipelines, and
their place therein is described. Also given are a few examples of how the
different tasks can be steered through the
DPU interface. For the interface
and use of every individual task, please read the corresponding
HOW-TO.
The atomic tasks that make up the calibration pipelines are summarized in Table
, together with their role in the
system and the identifier under which these are known to the DPU interface.
The sequence of tasks that make up the bias and flat field pipelines is shown
in Figure . The sequence of tasks that should be run for
the photometric calibration is shown in Figure . In these
figures, each one of the individual tasks is represented by one box. The arrows
indicate the flow of the pipeline, and the shaded parts show particular
(optional) branches therein.
The bias and flat field pipelines are pretty straightforward: no difficulties
or surprises here. Note, however, that after having derived the masterflat, the
processing continues in the photometric pipeline (hence the arrow at the end of
the line in Fig. ).
The photometric pipeline is more tricky than the bias or flatfield pipeline for
two reasons: (1) a piece of the image pipeline must be run to process the
photometric standard fields (hence the
http://www.astro-wise.org/portal/howtos/man_howto_reduce/man_howto_reduce.shtmlReduce
and
http://www.astro-wise.org/portal/howtos/man_howto_astrom/man_howto_astrom.shtmlAstrometry
boxes in Fig. ), (2) the optional branch of the
illumination correction is an iterative loop that in Fig.
actually runs backwards (characterising the illumination variation is more of
an interactive process)
Table:
The atomic processing steps that make up the various calibration pipelines and the identifiers through which these can be selected by the user
from the DPU interface. Note that not all processing steps are available through the DPU interface.
Pipeline |
Processing step |
Purpose |
DPU identifier |
Bias |
http://www.astro-wise.org/portal/howtos/man_howto_readnoise/man_howto_readnoise.shtmlReadNoise |
Deriving the read noise |
ReadNoise |
|
http://www.astro-wise.org/portal/howtos/man_howto_bias/man_howto_bias.shtmlBias |
Creating a master bias |
Bias |
|
http://www.astro-wise.org/portal/howtos/man_howto_hot/man_howto_hot.shtmlHotPixels |
Creating a hotpixel map |
HotPixels |
|
http://www.astro-wise.org/portal/howtos/man_howto_gain/man_howto_gain.shtmlGain |
Derive the gain |
Gain |
Flat field |
http://www.astro-wise.org/portal/howtos/man_howto_flat/man_howto_flat.shtmlDomeFlat |
Creating a domeflat |
DomeFlat |
|
http://www.astro-wise.org/portal/howtos/man_howto_cold/man_howto_cold.shtmlColdPixels |
Creating a coldpixel map |
ColdPixels |
|
http://www.astro-wise.org/portal/howtos/man_howto_flat/man_howto_flat.shtmlTwilightFlat |
Creating a twilightflat |
TwilightFlat |
|
http://www.astro-wise.org/portal/howtos/man_howto_flat/man_howto_flat.shtmlMasterFlat |
Creating a masterflat |
MasterFlat |
|
http://www.astro-wise.org/portal/howtos/man_howto_fringe/man_howto_fringe.shtmlFringeFlat |
Creating a fringeflat |
FringeFlat |
Photometric |
http://www.astro-wise.org/portal/howtos/man_howto_makephotcat/man_howto_makephotcat.shtmlPhotCalExtractResulttable |
Measuring fluxes of standard stars |
Photcat |
|
http://www.astro-wise.org/portal/howtos/man_howto_zeropoint/man_howto_zeropoint.shtmlPhotCalExtractZeropoint |
Deriving the zeropoint |
Photom |
|
PhotCalMonitoring1 |
Monitoring the atmosphere |
- |
|
http://www.astro-wise.org/portal/howtos/man_howto_illuminationcorrection/man_howto_illuminationcorrection.shtmlIlluminationCorrectionVerify1 |
Characterizing illumination variations |
- |
|
http://www.astro-wise.org/portal/howtos/man_howto_illuminationcorrection/man_howto_illuminationcorrection.shtmlIlluminationCorrection |
Creating an illumination correction frame |
- |
|
- 1 This processing step is performed on a single node
|
Figure:
The order and flow of the atomic processing steps
|
Figure:
The order and flow of the atomic processing steps
|
Make master biases for all CCDs of OmegaCAM for a certain bias template:
awe> dpu.run('Bias', instrument='OMEGACAM', template='2014-07-04T10:39:28')
Make a twilightflat for the specified night and filter:
awe> dpu.run('TwilightFlat', i='OMEGACAM', d='2014-06-29', f='OCAM_r_SDSS')
Make photometric catalogs from a particular standard field exposure:
awe> dpu.run('Photcat', i='OMEGACAM', raw=['OMEGACAM.2014-04-26T23:55:32.384_32.fits'])