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Separate VLA images:

  • NVSS (AllSky 1.4 GHz/45")
  • FIRST (SDSS 1.4 GHz/5")
  • Spitzer FLS (1.4 GHz/5")
  • VLSS (AllSky 75 MHz/80")
  • NRAO Image Gallery


    Version 2022-Sep-02 [an error occurred while processing this directive]

  • NRAO VLA Archive Survey Code Page

       [AVLAPREP.001]   [AVLAPIPE.001]   [AVLAPIPE.HLP]   [AVLAPOST.001]  

    The NRAO VLA Archive Survey (NVAS for short) pipeline consists of some PERL scripts that interact, using a UNIX command line interface, with the VLA data archive and a current version of AIPS with the AIPS procedures defined below. We are keeping the PERL scripts and local logistical files to our selves for now, as they are mainly tuned to our local environment to run bulk pipelines. However, the AIPS procedures are public and summarized below. They probably will end up in the AIPS distribution later.

    When you have calibrated your data using the VLA data calibration pipeline, or even used part of the code, it would be appreciated if you would mention the VLA pipeline next to an acknowledgment to NRAO in the publication of your scientific results; e.g. "The VLA data was calibrated using NRAO's "VLA data calibration pipeline" in AIPS (Sjouwerman, 2006, in preparation)" [ask Lorant Sjouwerman]. Thanks!
    On my side I would like to acknowledge the efforts of the Cast of AIPS, in particular Eric Greisen, for making and maintaining the AIPS-tasks and environment needed to reduce VLA data (and any other radio astronomy data) in AIPS over the years.

    AIPS Procedures

    The AIPS procedure files consist of three different types of procedures; probably the most useful for the general user is the pipeline code itself (i.e. AVLAPIPE.001 and AVLAPIPE.HLP). Consult Chapter 12 of the AIPS CookBook on how to use RUN files and procedures in AIPS. Essentially there are:
    • AVLAPREP.001   (6.5KB)
      This is a collection of AIPS/POPS procedures to get a downloaded archive file into AIPS and perform some checks (such as deleting unwanted files, investigate the source list, convert to J2000 and move away data to other user numbers). These procedures are mainly logistical tricks for us to get the data "pipeline ready".
      It is probably not too useful for the general user.
    • AVLAPIPE.001   ( 28KB ) and AVLAPIPE.HLP   ( 20KB )
      These are the core VLA pipeline scripts, the ones that you're probably after. They are slightly modified versions of "VLARUN" already in the AIPS distribution, so you can try those directly if you do not get this download working (or if you want to skip it and start without hassle). The HELP-file, "AVLAPIPE.HLP", is needed as a place holder for your inputs (such as inname, inclass, solint, imsize, etc.). The AIPS/POPS procedures are in "AVLAPIPE.001". When installed correctly, (see section 3.10/3.10.2 (page 3-16/3-17) of Chapter 3 in the AIPS Cookbook), typing explain avlapipe in AIPS will give you all the help you need, that is, about this pipeline procedure. For example, if you also download NVASDEFS.001 in the same area and type run nvasdefs, before typing inputs avlapipe on a new line, it will show you the defaults used for NVAS.
      For general help on AIPS, read the AIPS Cookbook and perhaps, for synthesis imaging in general, the proceedings/handbooks from the NRAO Summer Schools: Synthesis Imaging in Radio Astronomy II.
    • AVLAPOST.001   (111 B )
      This is a collection of AIPS/POPS procedures to get a pipelined experiment into the VLA image (and calibrated data) archive.
      It is probably not too useful for the general user, maybe except for the writing out of image and data FITS files, if you don't mind standardized names for them.

    NVAS Contact

    Contact Lorant Sjouwerman for any remarks, suggestions and/or reasonable complaints. Compliments and encouragements should go to the division head (C. Chandler). Thanks for using this service! Modified on 2006-Nov-17 (text), 2006-Oct-31 (canvas)