CARTA is the Cube Analysis and Rendering Tool for Astronomy, a new image visualization and analysis tool designed for the ALMA, the VLA, and the SKA pathfinders. As image sizes continue to increase with modern telescopes, viewing an image with a local image viewer or with a remote image viewer via the ssh protocol becomes less efficient. The mission of CARTA is to provide usability and scalability for the future by utilizing modern web technologies and computing parallelization.
Download and Installation (see https://cartavis.github.io/)
CARTA is a separate application and not directly integrated with CASA. Refer to the official CARTA website for download and installation instructions as well as a proper set of documentation.
Note: CARTA does not yet offer an exact replacement for every feature in the old CASA Viewer (tasks imview and msview). Many things are complete, and CARTA offers a good deal of enhanced functionality over the imview task, but a small subset of things may still be missing.
Some advantages over the CASA Viewer (tasks imview and msview):
Much better performance, able to handle very large image cubes
Modern web browser based interface allowing local and remote display options.
Can display Stokes wedges.
Proper display of image headers
Flexibility to modify and save the layout
Supports new HDF5 image format (in addition to CASA Image, MIRIAD, and FITS)
Some remaining features of the CASA Viewer that are not yet in CARTA:
Position-velocity map generator
Complete set of fitting tools
Source finder tool
Tabular axis support
Subsequent releases of CARTA will continue to enhance CARTA’s performance. For a full overview of the current and upcoming features, see the official CARTA website.
Running CARTA at NRAO¶
The CARTA Website provides download links for CARTA on a variety of platforms and usage types. CARTA is intended for more than just CASA usage and supports installation within large data warehouses and archives. The specific usage mode relevant to most CASA users is running CARTA alongside a CASA instance to view the products produced by CASA. The Desktop version of CARTA is intended for this purpose.
If you are running CASA on your own laptop or workstation that you are directly using, then simply downloading and executing the Desktop version of CARTA for your OS is sufficient.
If you are connecting to a workstation, cluster node, or any other machine via ssh or VNC, you will need to run the Desktop version of CARTA in remote mode. This starts the CARTA backend and prints to the terminal a link that can be copied in to a web browser for connecting to the CARTA front end remotely.
The following example illustrates how to run CARTA within NRAO from home:
Connect home computer to the NRAO VPN and open a terminal
(Optional) Reserve a cluster node in the usual manner
$ ssh <username>@your_cluster_nodeor
$ ssh <username>@your_workstationfrom your home computer
$ carta --remote
Copy the link printed to the screen to your home computer web browser
Note: Your home computer must be on the NRAO VPN or it wont see the cluster node / workstation name.
If you want to run CARTA on a machine outside of the VPN, you must set up an ssh tunnel to get through the firewall. This can be done with the following steps (in terminal on home computer):
$ ssh <username>@ssh.aoc.nrao.edu
$ ssh <username>@your_cluster_nodeor
$ ssh <username>@your_workstation
$ carta --remote --port=2000 --fport=3000
In another terminal on home computer:
ssh -f -N <username>@gygax.aoc.nrao.edu -L 2000:<cluster node>.aoc.nrao.edu:2000
ssh -f -N <username>@gygax.aoc.nrao.edu -L 3000:<cluster node>.aoc.nrao.edu:3000
In the browser of the home computer, go to: