Guide to the NA Imaging Template
About this Guide
This guide provides an outline of the Imaging Script followed by the North America ALMA Science Center (NAASC) in producing manually imaged Quality Assurance 2 (QA2) products of interferometric data. This is intended to be used as a template to produce basic continuum and line images. Some sections of this template are only appropriate for certain datasets. Therefore, not all sections of code in this guide may need to be run in order to reach a final product.
The ALMA Imaging Pipeline Reprocessing guide should be used to create pipeline images of delivered data.
All example images were produced using ALMA Science Verification Data of TW Hya. More information along with the dataset can be obtained from the TW Hydra Band 7 Calibration and Imaging Guide.
Prepare for Imaging
Before you begin imaging, it is important to determine whether the data is manually or pipeline calibrated. The README file should state how the dataset was calibrated. If this is not the case, look in the script directory of the delivered data package. If you see a file named <ASDM UID>.ms.scriptForCalibration.py, the dataset was manually calibrated. If you see a filename PPR_<Member OUS UID>.xml, the dataset was pipeline calibrated.
It is recommended that you use the same version of CASA in which the original reduction was performed. Refer to the README file or CASA logs to see which version was used. Download CASA and check for operating system requirements before proceeding.
Instructions on restoring the calibrated measurement set should be found in the README of your delivered dataset. For most cases, this can be done by executing scriptForPI.py in CASA in the script directory.
# in CASA
execfile(“scriptForPI.py”)
Attached Scripts
Two template scripts are attached to this guide. These contain commands with minimal directions and are intended to be used by those more familiar with imaging.
Obtaining Analysis Utilities
Some optional steps in this guide use the Analysis Utilities package. If you wish to use any of these tasks, follow the link above for download and installation instructions.
CASA Basics
If you are new to interferometry or CASA, we recommend you follow the “First Look” Imaging Tutorials. In addition, many frequently asked questions can be found in the ALMA Knowledgebase. If you have additional questions after reviewing this guide, please contact the ALMA Helpdesk.
