CookbookMopsic

To run MOPSIC from all directories on your system you furthermore need to add to the same file the path where the MOPSIC executable is located:

Of course it is not mandatory to keep MOPSIC and the DAFs in the directories created by the tar. You may put them wherever you want.

MOPSIC pipeline scripts

defs_general.mopsic script: The database pipeline reduction scripts are developed to be easy be used on your local PC. To do so, you have to edit the script. Simply change the logicalforiramdbto false if it was set to true:

let foriramdb .false.   ! or let foriramdb no

This will set the input data directory and the default input list to the directory structure generated by the tar file and all DAFs to defaults, i.e. to the entries defined by MOPSIC_DAFS.

The main routines used for the data reduction are ooCSF.mopsic and mapCSF.mopsic

For some special purposes also special scripts are offered. They are obtained by changing some default variables set in map_defs or oo_defs correspondingly. Follow the suggestions described there.

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Mapping

• mapCSF.mopsic : (gridded phase difference - correlated signal filter general script formap reduction with sky noise subtraction

• mapNcsf.mopsic : (gridded phase difference - no correlated signal filter) map reduction without sky noise subtraction

• mapCSFrmx.mopsic : special scripts to reduce maps of relatively compact sources, <200" in diameter; it is not suitable for more extended and structureless sources but should give better sky noise subtraction for relatively compact sources.

• mapCSF0.mopsic : map reduction with sky noise subtraction for sources which are weak (for CSF) and more extended than 0.5*beam_separation; weak for CSF means with peak fluxes < ~5*rms in the final data of one bolometer (i.e. ~5*30 mJy/beam)

• mapCSFrmn_saa.mopsic: (gridded phase difference - correlated signal filter - shift and add) source structure is assumed to be smaller than 0.5*beam_sep.

OnOff

• ooCSF.mopsic : (onoff - correlated signal filter) reduces onoffs with sky noise subtraction

• ooNcsf.mopsic: (onoff - no correlated signal filter) reduces onoffs without sky noise subtraction

Both on-off scripts write the final results to 'source'.OOxx files. For solar system sources ("body") the corresponding scripts oo_ncsf_body and oo_csf_body are also within the tar. Note that the only one change between the "body" and the standard on-off scripts is the additional argument body within the oo-command.

MOPSIC uses a special method to calculate the chopped signal. This gives much better results than the straight difference of the signals obtained at both chopper positions. The method is described in the Dec. 2005 IRAM Newsletter. For some special purposes also special scripts are offered. They are obtained simply by changing some default variables set in map_defs and/or oo_defs correspondingly.

There is also a script ooCSF_multsou.mopsic whic allows to reduce on-offs of many sources. The user has to define the number of sources and the lists with the files. Those can be created from a general lis using the commad find objects write.

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Misc

In addition there are also scripts to reduce pointings (p_nshav.mopsic - without sky noise subtraction, p_shav.mopsic - with very simple sky noise subtraction), skydips (skydips.mopsic) and to calculate the RCPs (Receiver Channel Parameters) from calibration maps. T

he scripts in the subdir specials are special versions of the general pipeline scripts. They use some other settings than defined in map_defs (see the corresponding map_defs_*). They are therefore optimized for some special purposes (e.g. subtracting a source distribution before reduction, applying base level corrections subscan by subscan, using polygons to define the base range, ...).

In the subdir extras you will find some scripts useful for checking (e.g. chk_rc) or just displaying the data. The snr... scripts demonstrate how to calculate a signa-to-noise ratio map.

In the subdir simple you will find a script map.mopsic which can be used to reduce maps of simple sources, e.g. compact or extended. It should not be used if the source shows both compact and extended components !

To start MOPSIC type mopsic. Macros are called with @scriptname WEAKSOU (no extension needed). The argument WEAKSOU may have values no or yes and allows to optimise the data processing for weak sources, i.e. sources with peak flux densities below ~50mJy/beam in case of on-offs or ~200mJy/beam in case of maps. If you are using the default download structure you can reduce your data straight forward by calling your preferred script, e.g:

@mapCSF WEAKSOU    ! WEAKSOU may be yes or no

or

@ooCSF WEAKSOU     ! WEAKSOU may be yes or no

MOPSIC will read all observations from the mydata.LIST, select the corresponding type of observations (i.e. maps or on-offs) and display a list of these selected observations. Within the reduction scripts you have different possibilities to select the data you may want to process:

select name          ! select all observations of a specific source (combined result)
select name*         ! select similar source names (e.g. to create a mosaic of maps or on-offs done on different parts of a source)
select no name[*]    ! excludes observations from the LIST with defined source names (do not use the exclude command, it is not finished)

To have a help online just type:

? select or ? delete  !lists all possibilities

The command find objects [> #, write] might also help.

Typing c will continue the reduction. The final result will be written to a FITS file in case of mapping. The default output name is scriptname.fits. Note that MOPSIC will not overwrite any results obtained in a previous reduction, except for GDF-files. If you use the same script for a different source make sure you move the FITS file to a different name before starting the script again or - the better solution - create dedicated scripts for each source and change the default fits name. IF YOU DO NOT CARE OVERWRITING the prevoius results, use the GDF files as output.

To view the results on a graphic device, open the device (before or after you execute the script:

device image white (or black)
lut idl4  ! Choose color table

for maps:

plot [options] , e.g. plo scaling linear -30 100

for onoffs:

plot oo [options].

There are also some pl... scripts, which might help checking the data quality.

Since MOPSIC is under developement and still not fully integrated within the GILDAS software, no detailed manual is available so far. A help on individual commands, however, is available by typing: ? command or help command for GILDAS commands.

Almost all commands used for advanced data reduction can be found in the MOPSIC scripts. MOPSIC, however, offers a much broader range of applications including advanced planning functions for mapping and onoff observations, post-reduction data analysis and processing and even reduction of non-bolometer data (optical, IR, spectroscopy). If you have questions how to obtain the best results from your data do not hesitate to contact Robert Zylka (zylka@iram.fr ).

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Mopsic Displays

Figure 1. ONOFF Online Display

• Upper left: on-off RA/DEC map of all pixels. The RA/DEC 0/0 denotes the reference pixel for pointing.
• Upper right: center pixel (53): before/after skynoise reduction, i.e. correlated signal filter (CSF, red/green)
• Lower left:
  • A star denotes the result of the last sky dips, i.e. the sky emissivity at the source elevation CHECK
  • Output of 3 DC pixels to check for changes in the sky emissivity
    • upper: line of sight (los) opacity (showing elevation effect and others)
    • lower: total power
• Lower center:
  • noise in the data before/after the CSF (the plot before is/will be overplotted with the noise after the CSF, in this particular case the rms in the data after CSF is visible, the numbers above the plot 49.5/51mJy/beam give the rms values of the high frequency noise component)
  • gain 1 (in this particular case)
  • col*/nule/sfcz, i.e. pointing and focus offsets
  • throw 32", period 520msec, rotator angle 0
• Lower right: time series of 4 pixels (51, 52, 53, 54), before and after sky noise subtraction

Figure 2. Pointing Online Display

Figure 3. Skydip Online Display

Figure 4. ONOFF data reduction: Results

• subFig 1: Noise vs Time

• subFig 2: Is the average of Fig 3 vs time

• subFig 3: Red represents the central pixel (20 or 53) per # of subscans.

• subFig 4: Total power on the pixels (red is central pixel) after correlated noise removal.

Appendix

Notes for maps

Look at NoteMopsicMaps for some detailed explanation on the settings of the reduction.

Notes for OnOff

Look at NoteMopsicOnoff for some detailed explanation on the settings of the reduction

Mopsic Glossary

Some useful commands of MOPSIC:

• inDir FILE defines the directory for input data

• outDir FILE defines the directory for output data

• inList FILE loads the observational parameters from FILE.LIST

• base in time btorder performs polynomial fit of order btorder to the time sequences, i.e. to signal = f(time)

• base in subscans blorder performs polynomial fit of order blorder to signals as function of the scanning coordinate, subscan by subscan (i.e. row by row in a map)

• calibrate FILE reads the calibration data cal_factor(JD) from the file FILE; the units might be counts/Jy or Jy/counts

• calibrate default reads the calibration data defined in the DAFs, i.e. the calibration data base

• calibrate dividing signal[Jy/beam]=signal[counts/beam]/cal_factor[counts/Jy] as function of the Julian date JD; the calibration data must be read in before

• calibrate multiply signal[Jy/beam]=signal[counts/beam]*cal_factor[Jy/counts] as function of the Julian date JD; the calibration data must be read in before

• calibrate back signal[counts/beam]=signal[Jy/beam]*cal_factor[counts/Jy] or signal[counts/beam]=signal[Jy/beam]/cal_factor[Jy/counts] as function of the Julian date JD; the calibration must have been applied before

• convert [options] converts either (Az,EL) to (RA,DEC) coordinates or (RA,DEC) to (l,b)

• correct extinction corrects for the atmospherical extinction, the zenith optical depth values must be loaded before (see the tau-command)

• correct ge corrects for the gain-elevation dependance

• delete dc deletes the data of the "total power" bolometers

• delete rc default deletes the data of the bolometers which are defined in the DAFs, i.e. the calibration data base

• finish finishes a subprogram, e.g. CONVERT, CSF, COMBINE, AE_OBS, REPROJECT, ...

• focus reduces the focus

• grid xinc grids the data in the scanning direction only, i.e. no 2dim or 3dim gridding

• plot [something] plots either the map in memory or sometihig else; the plotting device must be defined before (devide command)

• pointing reduces the pointing

• read ... /phases reads the data of both wobbler positions (the "phases") as independent time sequences

• read ... /pha dif reads the data of both wobbler positions and calculates the sequential differences as follows signal(i) = phase_left(i)-phase_right(i)

• rms [options] calculates the rms in the data

• run executes a subprogram, e.g. CONVERT, CSF, COMBINE, REPROJECT, ...

• scan # [/name NAME] reads raw data of scan # The option /name must be defined at least once or the scan name NAME must be set with set scan_name. The scan name NAME must include a * at the position of the scan # and the extension defining the format, e.g. iram30m-abba-20060120s*-imb.fits

• show rcp plots and prints the Receiver Channel Parameters

• select something selects the files from the input list (loaded with the command in_list) according to the defined selection criteria

• set scanName NAME sets the name of files for the command scan. The scan name NAME must include a * at the position of the scan # and the extension defining the format, e.g. iram30m-abba-20060120s*-imb.fits

• set scanDate DATE sets date in the file name used with the scan command; the format of DATE is YYYMMDD, e.g. 20060121

• store [something] stores either the current map in the backup buffer or something, e.g. the weighting

• tau default timeInterval reads the zenith optical depth values from the file defined in the DAFs, i.e. the calibration data base

• write fileName [/format formatName] writes the data to the file fileName in format determined by the extension of fileName, e.g. gdf, fits ... [in format specified by the option /format formatName]

• write +addName [/format formatName] writes the data to the file with name = inputDataFileName+addName

• CSF Correlated Signal Filter; as the correlated signal should be mostly the sky noise, it filters out the sky noise, the csf-command calls the sub-program CSF

• DBF Double Beam Filter (EKH, 1979)

• DBR Double Beam Restoration (i.e. deconvolution, EKH, 1979)

• > # [rms] clips the data above # [*rms]

• < # [rms] clips the data below # [*rms]

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