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For the user, [rgb]1,0,0IMAGER reduces the number of actions to the strict minimum.
The imaging sequence is always the same:
1- Reading data
READ UV MyData.uvt /RANGE Min Max Type
! here, optionally use UV_TIME, UV_COMPRESS, UV_BASELINE to average data
! or UV_FILTER, UV_CONT to filter lines or remove continuum
2- Imaging
UV_MAP
3- Deconvolving
CLEAN
! here, optionally use UV_RESTORE
4- Looking at the result
VIEW CLEAN ! or SHOW CLEAN
5- Writing the result
WRITE * MyData
- Step 1: Reading the specified internal buffer (here
UV) from the input file (cyan.uvt file type), loading only the channels falling in
the range defined by the variables Min and Max, of Type magentaCHANNEL,
magentaVELOCITY or magentaFREQUENCY. [rgb]1,0,0IMAGER recognizes whether the UV
table is for a single field or a mosaic. The only difference between
the single field and mosaic cases is that [rgb]1,0,0IMAGER yields a Sky
brightness image for Mosaics, while the computed sky brightness of a
single field is not automatically corrected for the primary beam
attenuation. Imaging for multiple fields will be presented in Section
.
Single Dish data can also be loaded in the following way :
magentaREAD SINGLE cyanFile.
- Step 2: Computing a dirty map and beam from a UV data.
magentaUV_MAP processes single fields as well as Mosaics.
- Step 3: Deconvolving the blueDIRTY image map (a Single-field or Mosaic)
using the dirty blueBEAM with the current blueMETHOD. The default
for the SIC variable blueMETHOD is magentaHOGBOM, the other
supported methods being magentaCLARK, magentaMRC, magentaMULTI and
magentaSDI. See magentaCLEAN ? for the other SIC variables
controlling the deconvolution process. The outputs are the blueCLEAN and
blueRESIDUAL images, and the Clean Component Table blueCCT, all being stored
in dedicated SIC variables.
- Step 4: Plotting the result in the specified internal
buffer (blueCLEAN). Optionaly, the user can restrict the plot to a
subset of channels through the optional arguments First and Last.
magentaSHOW CLEAN can also be used instead, and produces a different
type of plot.
- Step 5: Writing all modified image-like buffers (not
the UV tables) under the common file name ''cyanMyData''. In the case of the
present example, the following files are produced: cyanMyData.lmv,
MyData.lmv-clean, MyData.cct, MyData.beam, which correspond to the
buffers: blueDIRTY, blueCLEAN, blueCCT, and blueBEAM, respectively.
magentaWRITE UV cyanMyData would only write the internal buffer (blueUV) in the
file cyanMyData.uvt (the default extension corresponds to the specified
buffer data type).
Next: Getting Help: the HELP
Up: IMAGER principles
Previous: Implementation issues
Contents
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Gildas manager
2023-06-01