The RTDC
Processing SMA Data
1.2 m Telescopes
AST/RO
Extra

An Overview of SMA Data Reduction


Useful links before you start

What are the files in the SMA data directory?
SMA Data FAQ
Getting an overview of your data


Reducing the size of your data

The SWARM correlator has a fixed bandwidth and resolution, so file sizes in excess of 100GB are increasingly common. You may wish to reduce the size of your data file by rebinning the spectral data cube. This is especially important if you plan to use MIR, as it has a memory requirement of 2-3x the data size. The SMA provides a custom tool for rebinning SMA data: SMARechunker. You can expect the data size to scale linearly with the rebin factor.

Reducing the Size of your Data (RTDC)
Reducing the size of your dataset (SMARechunker) (SMA)


Calibrating SMA data

We currently recommend using MIR, an IDL based package tailored for the SMA, to calibrate your data. This is well supported at the CfA and expertise is available. MIR only performs calibration steps, however data can be written out in either MIRIAD or uvfits format, allowing MIRIAD or CASA to be used for cleaning and imaging.

SMA Data Calibration with MIR/IDL (RTDC)
The MIR Cookbook (SMA)

CASA can also be used for calibrating SMA data, however, until recently SMA could not be converted to a CASA compatible format. As such testing has been limited and we do not offer any support in this area. If you would like to explore this option there are tutorials, be warned however some may not be compatible with newer versions of CASA.

SMA CO Line Data 3.2 (NRAO tutorial)
SMA CASA Website (see 'Calibrating SMA Data with CASA' tab)

MIRIAD too is capable of calibrating SMA data, however we do not recommend it. MIRIAD frequently encounters problems reading SWARM datasets. If you chose this route you can find guidance on the MIRIAD home page.

Polarization data requires specialized tasks which are available in both MIR and MIRIAD.


Imaging SMA data

Either MIRIAD or CASA can used to image SMA SWARM data. We do not support using CASA for imaging older ASIC data however. Data calibrated with MIR can be written out in MIRIAD format or uvfits for CASA.

MIRIAD for SMA Data (RTDC)
MIRIAD Software for SMA (SMA)
CASA for SMA Data (RTDC)
SMA CO Line Data 3.2 (NRAO tutorial)
SMA CASA Website (see 'Imaging SMA Data with CASA' tab)


Summary

MIR/IDL
MIRIAD
CASA
AIPS
Calibration
Imaging
Can read raw SMA data
Well supported
(recommended)

MIR, MIRIAD and CASA are all available from the RTDC, CF and Hilo (SMA users only) machines. AIPS is available from the RTDC only.


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