Calibration Tables and Logs

Calibration Tables and Logs

Calibration Tables and Logs

Automated calibration transfer for VLBA correlator output

Your data includes automated calibration transfer tables for data from the VLBA correlator. These transfer tables of calibration information include data from the 10 VLBA antennas, as well as selected information from the High Sensitivity Array antennas (VLA, Green Bank, Effelsberg and Arecibo) which currently provide VLBA-style monitor data. Significant changes to AIPS have been required to introduce calibration transfer. To take advantage of new tools and current updates, it is highly recommended that users download the latest version of AIPS. Help files for a number of AIPS tasks have been updated to reflect the new calibration procedures.

Please send comments and bug reports to the HelpDesk and select VLBA.

Obtaining calibration and log files


Antenna Gains File: The vlba_gains.key file, containing VLBA zenith sensitivities and gain curves, with an explanatory preamble may be obtained using anonymous ftp. This file is not needed in most cases, the data received from NRAO should have GC tables attached.

To obtain this file:
ftp ftp.aoc.nrao.edu (or 146.88.1.10)
Name: anonymous
Password: your e-mail address
ftp> cd pub
ftp> get vlba_gains.key
ftp> quit
Calibration and log files and plots: There are log and calibration files available on the file server vlbiobs. Many of them will be useful when examining and calibrating your data. The "tsm" plots are one of the most useful, they are a set of plots that give information specific to individual antennas (system temperature, weather and pulse cal information). Below is a description of all the files.

These files can be accessed on the web at http://www.vlba.nrao.edu/astro/VOBS/astronomy/, then click on the mmmyy and pppppp for your experiment. Where mmmyy is a code for the month and year of the beginning of your program (e.g., if the program was observing in October 2012, then the mmmyy is oct12) and ppppppis your program code. These files are:
  • pppppplog.vlba: VLBA observing log containing comments entered by the array operator. File is automatically e-mailed to observers whose addresses are known to VLBA operations.
  • ppppppcal.vlba.gz: Gzipped VLBA calibration file containing system temperatures, flagging information, pulse cal and weather station data, scan summaries, and VLBA tape recorder information for all available VLBA antennas. File is not needed in most cases, the data received from NRAO should have the TY, FG, PC, and WX tables attached.
  • pppppptsm.XX.ps.gz: Gzipped PostScript plots of selected data from file ppppppcal.vlba.gz for each available antenna with station code XX = SC, HN, NL, FD, LA, PT, KP, OV, BR, MK, or Y. These usually include plots of the system temperature, weather information (wind speed and direction, temperature and dew point, atmospheric pressure and amount of precipitation), and pulse cal data. All of these plots are useful in determining the quality of the data from individual antennas.
  • pppppplog.y: EVLA observing log containing comments entered by the array operator, if EVLA was used. File is automatically e-mailed to observers whose addresses are known to EVLA operations.
  • ppppppcal.y.gz: Gzipped EVLA calibration file containing calibration information for all EVLA polarizations and IFs, if VLA was used. File starts with an explanatory preamble. File is not needed in most cases, the data received from NRAO should have the TY, FG, PC, and WX tables attached.

Connect with NRAO

The National Radio Astronomy Observatory and Green Bank Observatory are facilities of the U.S. National Science Foundation operated under cooperative agreement by Associated Universities, Inc.

Founded in 1956, the NRAO provides state-of-the-art radio telescope facilities for use by the international scientific community. NRAO telescopes are open to all astronomers regardless of institutional or national affiliation. Observing time on NRAO telescopes is available on a competitive basis to qualified scientists after evaluation of research proposals on the basis of scientific merit, the capability of the instruments to do the work, and the availability of the telescope during the requested time. NRAO also provides both formal and informal programs in education and public outreach for teachers, students, the general public, and the media.

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