CASA Release Notes (Version 3.0.2)

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Previous Releases:

Release Notes: Release 3.0.1

The current CASA Release

The current CASA release is Release 3.0.2

This release (3.0.2) is a patch to the 3.0.1 release. The patch is mainly driven by the first light of the EVLA. CASA, however, is still under development, and some features might change in future releases. This should be taken into account as users begin to learn the package. We will do our best to point out commands, tasks, and parameters that are likely to change underfoot. Although many bugs were eradicated in the Beta Release stage, there are some that persist. We will do our best to stamp these out as soon as we find them. See the release notes for the current version for more details.

We occasionally issue patches to the current release in between formal releases. Please check these pages regularly to look for updates to the release and the documentation, and to check the list of known problems. You can find the contact information for feedback here also.

Note that in its current incarnation CASA is designed to support EVLA, ALMA, and VLA data. Data from other telescopes, be it single dish or interferometers can be imported from uvfits or sdfits formats into measurements sets (ms) or scantables in CASA. Given the variety of non-standard fits formats, we cannot guarantee that CASA will fully support data from all telescopes. However, efforts are made to support data formats from other facilities.

Obtaining the CASA Release

See for information on how to obtain CASA.

Supported Platforms

Note that we provide two flavors of CASA binaries for installation:

Linux:
- Both 32-bit and 64-bit are available
- We test on RHEL 5 extensively, and do limited testing on Ubuntu, OpenSUSE, and Fedora. Most linux flavors are thought to work, please let us know via the http://my.nrao.edu CASA helpdesk if you encounter one that does not.
Macintosh OSX 10.5 and 10.6 (Intel Macs only):
- The Mac build is 32-bit, but runs fine on 64-bit machines. A 64-bit version is anticipated for the next patch.
- MacOSX 10.4 is no longer supported

CASA Release Notes:

Valid for CASA Release 3.0.2 and later:

Release 3.0.2 is mainly intended to be a patch to the previous 3.0.1 release of CASA. It is timed to coincide with the first scientific data delivery from the EVLA. However, many improvements to the code have been made and a number of bugs have been fixed. The improvements include:

Flagging
- up to 30% speed improvements in flagdata, in particular for data with many spectral windows
Imaging
- new task csvclean to support ALMA commissioning. This task does an invert of the visibilities and deconvolve in the image plane. This task does not do a uvdata subtraction (aka Cotton-Schwab major cycle) of model visibility as in clean
- clean: 'chaniter' is now separated from the 'interactive' parameter and available for 'channel', 'frequency' and 'velocity' modes. Cleaning sequencially by channel is now available not just for interactive but also for non-interactive clean
Data examination/editing
- ms.msseltoindex now returns list of channels only those channels selected by the "spw" parameter. It also now returns the baseline/antenna selection.
- listvis can read FLOAT_DATA columns from single dish MS. Also: improved listing of auto-correlation MS on a Mac
- In plotms, improved "locate" output format using field and antenna names, instead of indices
- In plotms, new axes choices supported (when not averaging): Wt, ImWt
- plotms will plot caltables. NB: This is still under development and should be used with caution. Many gui options---e.g., averaging, transformations, some axis options---are not supported, even though they appear to be available.
Calibration
- new parameter 'minsnr' in bandpass for channel based, 'B', solutions. 'minsnr' defines the signal to noise threshold for a solution to be valid
- The EPJones table now has separate pointing offsets for the two polarizations
- New gaincurves for the EVLA, and some bugs fixed in gaincurve application
- Channelized R-L phase calibration now supported in polcal via poltype='Xf'.
- Provisional "Perley-Butler 2010" flux density scale now supported in setjy. NB: the default is still "Perley-Taylor 1999", until the authors complete their analysis. "Perley-Butler 2010" is recommended for high VLA/EVLA frequencies (> 15 GHz) as it is bootstrapped to the absolute flux density calibraiton of WMAP using planets at the higher frequencies.
Data and Image Manipulation
- the default interpolation method in spectral gridding within clean and cvel is now set to 'linear' instead of 'nearest'
- immath : mode 'pola' and 'poli' calculations now can be done if a single, multi-stokes image is provided; added linear polarization intensity threshold for 'pola'
Simulation
- introducing a new task interface simdata2: modular / independent execution of subtasks: modify sky model, calculate mosaic pointings, predict visibilities, (re)image the data, and analyze the simulated image
- simdata2 incorporates single dish capability from sdsim, including joint deconvolution of simulated total power and interferometric data
- the old simdata and sdsim tasks are preserved for backward capability, with some bugs fixed.
Data im/export
- exportuvfits now has a parameter padwithflags which allows users to add flags to missing data sections if combinespw is set. With both parameters set, exportuvfits will export the spectral windows as IFs
- importevla task has now an option to write autocorrelation and/or crosscorrelation data to an MS. The task can also flag all data that come as zeros
Single Dish
- header, panel layout, and legend location control for sdplot. Also a new parameter 'plotstyle' is added to allow more flexibility in arranging plots.
- sdsim has new options 'checkinputs', 'fidelity', and 'display' for improved plotting flexibility.
- asapplotter has now options to change the panel layout
- msmoments now also works on single-dish measurement sets. Added subparameters for data selection; 'includerow' and 'excluderow' were renamed to 'includemask' and 'excludemask'
Other
- up to 2.5 times speed improvement in the creation of scratch columns ('model' and 'corrected_data' columns)
- 'rm -r' within CASA is now calling shutil.rmtree for cleaner removal of datasets and tables

For more information, see the Known Issues and FAQ page, and for general reference see the Help and Documentation page.

This code is available under the terms of the GNU General Public Lincense

Modified on Monday, 26-Jul-2010 17:52:47 EDT