Obit - Astronomy Software for Algorithm Development
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Overview
Obit is a group of software packages for handling radio astronomy
data, especially interferometric and single dish OTF imaging.
This software is made available under the GNU General Public License
in the hope that it might be useful but "as is" with NO GUARANTEE OR
ASSURANCE of suitability, usability or correctness for any purpose.
Obit is developed and maintained by Bill Cotton at The National
Radio Astronomy Observatory in Charlottesville, Virginia, USA.
Obit is intended primarily as an environment in which new data
processing algorithms can be developed and tested but which can also
be used for production processing of a certain range of scientific
problems.
Obit is a Unix software environment with a limited set of developed
applications.
It is an object--oriented set of class and utility libraries
allowing access to multiple disk--resident data formats.
In particular, access to either AIPS disk data or FITS files.
A number of low level applications are implemented such as imaging and
deconvolving interferometer or OTF data,
High-level applications may be either compiled c programs or python
scripts; most of the high-level operations have bindings to python.
Obit applications are interoperable with Classic AIPS and the ObitTalk
python interface gives access to AIPS tasks as well as Obit libraries
and tasks.
A
preprint of a paper describing the Obit package (PASP, 2008, 120,
439) is available.
Documentation
Software Documentation
-
ObitTalk User documentation.
-
ObitTalk Software (python) architecture documentation.
-
Obit Software (c) architecture documentation.
-
Obit single dish (c) software architecture documentation.
-
doxygen generated Obit C language documentation.
-
doxygen generated Obit Single dish C language documentation.
Obit Algorithmic Development Memos
-
pdf Image Pixelization and Dynamic Range (EVLA memo 114).
-
pdf Automatic CLEAN Windowing (EVLA memo 116) .
-
pdf Beam Squint and Stokes V on the VLA (EVLA memo 113).
-
pdf Ionospheric Effects and Imaging and Calibration of the VLA (EVLA memo 118).
-
pdf Ionospheric Effects and Calibration of the VLA at 327 MHz (EVLA memo 117).
-
pdf Tools for Ionospheric Studies (EVLA memo 115).
-
pdf Users guide to Obit software for Mustang (GBT 3 mm bolometer
camera).
Presentations related to Obit
-
pdf W. Cotton, Presentation giving high level description of Obit
and a discussion of the autoWindow feature.
-
pdf ,
ppt
J. Uson, Application of the Squint beam squint correction to
VLA HI observations of super thin galaxies.
-
pdf ,
ppt
J. Uson, Steps towards a VLA or ALMA pipeline.
Using Subversion to obtain Obit
The anonymous server allows you to get the most up-to-date version
of software and then do updates to the software.
To checkout the Obit installation package from Subversion, including
most third party software:
% svn checkout https://svn.cv.nrao.edu/svn/ObitInstall/
This will checkout the installation package described below.
This software can be installed as described in the
README file.
Updates are then possible using:
% svn update
The Subversion server has a
Web based browser that displays the current state of the repository.
Obit Installation
There is now an experimental installation package that includes the
required third party software and an installation script.
The
tarball is available here and
README is available here.
This has only been heavily tested under RHE4 LINUX although successful
installations are reported under RHEL5 and Ubuntu.
Obit software obtained using this installation can later be
updated using the Subversion interface as described above.
Obit Components
There are several components of Obit and related software.
This and required third party software can be obtained as described above.
Obit
This is the basic Obit package supporting astronomical images and
radio interferometry data and applications.
ObitSD
Ths is a single dish "On-the-fly" (OTF) imaging addon to Obit.
Only FITS format files are supported.
ObitSD requires Obit.
ObitView
This is a Unix/X-Windows program that serves as an Image display
server.
Communications is through the xmlrpc protocol.
It is currently usable by Obit and ObitSD to display images and
interactively select CLEAN windows.
ObitView can browse and display FITS images or local AIPS images can
be displayed if requested via the xmlrpc interface.
ObitView requires Obit.
ParselTongue
ParselTongue is a python-based scripting and interactive command line
interface to astronomical data processing packages.
ParselTongue can execute AIPS or Obit tasks (compiled programs) and use the
Obit python interface in a script.
ParselTongue is an EU funded component of RadioNet and is being
developed by the Joint Institute for VLBI in Europe (JIVE).
ParselTongue documentation is available
here
ObitTalk
ObitTalk is derived from ParselTongue but with more interactive
enhancements.
User documentation is available
here
as well as in extensive on-line documentation.
The (USA) National Radio Astronomy Observatory
(NRAO)
is operated by Associated Universities, Inc. and is a Facility of
the (USA) National Science Foundation.
Comments? Questions? Problems?