Dear PI,

The data for for project BB222G on 01 Apr. 2006 has been correlated.
The contact person for this project was Vivek Dhawan. 

    !Auto-released VLBA Correlator Output!
    --------------------------------------
This project has been auto-released.  Please carefully consult the 
VLBA system monitoring reports near the observation date of this 
project and examine the data quality plots on the vlbiobs file server 
The location and description of these reports and plots are described 
below. 

1. For possible problems and additional information which may have
   affected this observation, please consult the VLBA System Monitoring 
   page located at the Internet URL:
   http://www.vlba.nrao.edu/astro/VOBS/astronomy/vlba_sysmon.html
   Select (click on) the link for the 2006 VLBA System Monitoring Calendar.
   Then select (click on) the monitoring project code(s) 'MT***'
   that observed during the concurrent week for this
   observation.  This will display the selected monitoring project directory
   where a report summary named monitor.txt can be viewed or retrieved.
   This directory also contains useful plots under reference antenna
   subdirectories.

2. Operations staff have devised a web browser to navigate the file server
   vlbiobs, as well as view and retrieve its text and PostScript files,
   gzipped or not. This browser can be reached through the VLBA homepage at
   http://www.vlba.nrao.edu/astro/VOBS/astronomy/.
   All of the files mentioned above can be accessed either
   with this browser or by FTPing to the vlbiobs account on vlbiobs.

3. Tape weights versus time plots have been generated for the entire time range
   of your experiment. These are a measure of tape record/playback quality,
   representing the fraction of valid data samples. Data with weights below
   70-75% should be flagged. However, you may want to be more cautious
   when dealing with non-VLBA stations.  The easiest way to estimate
   the best weight threshold is by looking at the tape weights vs. time
   plots generated here.  You can find the weights plots at
   http://www.vlba.nrao.edu/astro/VOBS/astronomy/apr06/bb222g/sniffer
   /wtsfile.ps.  If your experiment involves more than one distribution tape
   then there may be a tape# subdirectory between the /sniffer and wtsfile.ps.
   See /home/vlbiobs/README.sniffer for instructions on how to interpret this
   plot.

4. Delay, rate, phase, and amplitude plots were made for the observation.

5. Autocorrelation bandpass plots were generated for all antennas for scans
   on all sources.

6. Cross-correlation bandpass plots were generated for all baselines to LA
   for scans on all sources.

7. Gzipped PostScript plots of Tsys and other monitor data for each available
   VLBA antenna can be found at:
   http://www.vlba.nrao.edu/astro/VOBS/astronomy/apr06/bb222g.

8. The jobs associated with the correlation of BB222G can be found at:
   http://www.vlba.nrao.edu/astro/VOBS/astronomy/apr06/bb222g/jobs.
   These files provided the correlator with all ancillary data
   needed for VLBI, including:  correlation parameters and telescopes
   correlated in the final production.
   The job numbers are: 7420 - 7424


   Automated Calibration Transfer for VLBA Correlator Output
   ---------------------------------------------------------
The first phase of automated calibration transfer for data from
the VLBA correlator has been completed, and was used
for your observation.  This transfer of calibration information includes
data from the 10 VLBA antennas, as well as selected information from the VLA
and Effelsberg, which currently provide VLBA-style
monitor data.  Significant changes to AIPS have been required to
introduce calibration transfer, so users must have the patched
version of 15OCT98 AIPS, or any later version, beginning with 15APR99.
It is highly recommended that users download the 31DEC03 version
of AIPS to take advantage of new tools and current updates.
Help files for a number of AIPS tasks have been updated to
reflect the new calibration procedures.  There also is a new
version of the VLBI chapter of the AIPS cookbook, available
from http://www.cv.nrao.edu/aips/aipsdoc.html, that includes
more details on how to cope with the calibration transfer process.

The calibration-transfer process relieves observers of the
burden of creating and inputting calibration files for VLBA
antennas.  Instead, this information is now provided as tables
attached to the FITS data sets output by the VLBA correlator.
The ancillary data include antenna gain (GC table), system
temperature (TY table), pulse calibration (PC table), flags (FG
table), and weather (WX table).  The wise observer will not
modify these original tables; processing errors might then force
the data to be reloaded using FITLD.  See the description of
MERGECAL in Section 9.2.1.7 of the new cookbook chapter for more
detail.  Of course, skeptical users can simply delete the appropriate
tables created by FITLD and generate their tables in the old manner.

At present, ancillary data from most external telescopes must still
be loaded in the old manner, and observations of strong sources
may be needed for manual pulse calibration at those telescopes.
Up-to-date instructions on coping with observations including
external telescopes can be found at
http://www.vlba.nrao.edu/astro/obscor/cal-transfer/.

Please send comments on calibration transfer to julvesta@nrao.edu, 
and send bug reports to daip@nrao.edu, with a copy to julvesta@nrao.edu.


   End of Letter