Introduction to Miriad for CARMA users

A new miriad data-reduction carma-specific cookbook is now available: (as draft)

Usage Setup

From the Unix point of view MIRIAD is a set of programs that you can execute from the command line. So your Unix search path needs to be modified for this. For most situations something like
	source /usr/local/miriad/miriad_start.csh
will do, but check your local variations on the path name. For example, Maryland uses a method referred to as astroload. At CARMA, depending if you are in the Owens Valley or at Cedar Flat, you would use /sw/miriad/cvs/ or /array/miriad/cvs/ resp.


All MIRIAD programs need a supply of "keyword=value" pairs on the command line. Often many take up a reasonable default, but keywords such as the input file and the plotting device often do not have a default.

The "miriad" shell

Some users, particularly if unfamiliar with a program's inputs, prefer using MIRIAD via an AIPS-like shell called "miriad". This is where you can select a task to run, inspect and set its parameters, and run the task. Start the miriad shell by typing "miriad". Then you can list a program's keywords and any values that are set by typing e.g. "inp uvplt". You can assign values to the keywords with "keyword=value" (e.g. vis=myfile.vis), check its inputs again by just typing "inp", see explanations of the program and its keywords by typeing "help", and then running it with "go". Keyword values are saved until overwritten or explicitly unset. The command "mirhelp miriad" gives some more details.


The commands "doc" and "mirhelp" .... they explain all the keywords, their meaning and defaults.

Visibility Data Inspection

The data at CARMA are written in MIRIAD visibility format. Here are some frequently used programs to inspect, visualize and calibrate these data.

Data Calibration and Manipulation


Once calibrated, conversion to an image (the FFT stage) and deconvolution can be done with the following programs:

Image Data

Images (and cubes) can be inspected and visualized with the following tools:

Starting with no data

If you have no data yet, and would still like to get started, two programs, depending on what flavor of data you want to use, are useful:

uvgen: Visibility Data

This program needs a few small text files for the description of the source and the antenna configuration. There are examples and templates in the $MIRCAT directory. Here is an example for continuum data:
  % uvgen out=vis1 source=$MIRCAT/point.source ant=$MIRCAT/carma_de.04oct.ant telescop=carma 

imgen: Image Data

This program creates maps or cubes, and is very easy to use. Example:
  % imgen out=map1 object=gaussian spar=10,0,0,20,10,30 


Some readers really want to know this ..... but installing MIRIAD on your own machine is actually easy, assuming you have all the right tools, compilers etc. installed. It is known to work out of the box on most Linux and MacOSX machines.. On the simplest level it can be done with the following two commands:
  curl | tar zxf -
after which you can do
  source miriad/miriad_start.csh
If that doesn't work, please refer to the MIRIAD installation guidelines.
Page last modified: Wednesday, 11-Jun-2008 12:50:34 EDT by PJT.