From: <stingay_at_email.protected>
Date: Fri, 2 Jun 2006 10:02:23 +1000 (EST)

Hi Jim,

I, and others, have been agitating for changes to the calibration
procedures for the LBA, to address issues such as you have brought up -
for a long time. I think we all recognise that this needs to happen. The
question is, as usual, who has the time?

At the ATCA and Parkes, the method by which the Tsys information is logged
makes it a pain for the observers to extract the AIPS-readable tables for
every experiment. It is a significant adition to the workload for the
observers and I don't think it is a task that they should be responsible
for. Historically, calibration has been the responsibility of the PI - we
have all struggled with it from time to time but generally it works ok.

However, our calibration has gone backwards recently, for a number of
reasons. In addition, Leith's observations seem to have sufffered from an
additional specific problem at the ATCA in March. I suspect that it may
have something to do with changes to CATIE, but I am not sure. Anyway,
the calibration of this experiment is going to be more problematic than
usual. I'll note that this happens from time to time at all antennas -
when Tsys information is not recorded for some reason. I'm sorry that I
don't have time to go into this myself in detail at the moment.

We need someone to take a leadership role on calibration. Someone from
the ATNF, I would argue. We need some reasonably efficient and automated
way to compile all the calibration data, at least from the ATCA, Mopra,
and Parkes. Hobart, Ceduna, and Tid seem to have good systems in place.

Lots of ideas have been thrown around over the years, and a few
implemented. We need to take the next step.

With regard to the shift of correlation to Swinburne, we are entering into
a contract with the ATNF. This document sets out the deliverables (i.e.
what the ATNF get and what is delivered to PIs as post-correlation
products) and performance criteria. It is all documented. I can confirm
that we will not be responsible for any aspect of calibration, other than
advising the PI what Tsys in Jy has been applied at the correlator. This
reflects what is currently done at the S2 correlator.

I would love to be able to attach Tsys and gain tables to the data. It
would be easy with the software correlator. If we had a robust scheme to
produce good calibration files in some format, then we could work on
including them with the correlated output. This will not be a part of our
contracted obligations, however.

In fact, I would make this suggestion. If someone can determine a scheme
to automatically collate the Tsys files in their native formats, from each
antenna, on the ATNF ftp site, the functionallity of logs2keyin could be
incorporated into a pre-correlation step at Swinburne. This would remove
the problems of multiple versions of logs2keyin floating around and would
consolidate the process in one place.

I'd be willing to work on this from our end, if someone can be identified
on the ATNF end to put some time into this.

Cheers, Steven

##=====================================================##
Dr Steven Tingay stingay_at_astro.<!--nospam-->swin.edu.au
Swinburne SKA Project Leader
Associate Professor

Centre for Astrophysics and Supercomputing
Swinburne University of Technology
Mail No H39
P.O. Box 218, Hawthorn, Vic. 3122, Australia

ph: +61 3 9214 8758
fax: +61 3 9214 8797

http://astronomy.swin.edu.au/ska
##=====================================================##

On Fri, 2 Jun 2006, Jim Lovell wrote:

>Dear VLBIers,
>
>I'd like to make a request regarding calibration (Tsys and flag) files. Is it
>possible for observatories to provide AIPS-readable input files along with
>logs following the experiment? I know that UTas and Tid do this already but it
>doesn't happen at Mopra or the ATCA and Parkes files don't seem to end up on
>the FTP site automatically.
>
>If these files are prepared straight after the experiment by the observer then
>it makes it a heck of a lot easier for the PI. Leith and I have been
>struggling to interpret the ATCA and Mopra Tsys logs which seem to be either
>non-standard or to have changed recently because logs2keyin produces strange
>output. Working out what happened and how to get what we need is impossible
>without hassling the people who made the observations in the first place. So
>it seems better all round for the files to be produced by the observers.
>
>And while I'm sticking my neck out, could I make one more suggestion? With the
>move of correlation to Swinburne, will there be some sort of LBA operations
>document written that describes who is responsible for what? If so, could this
>document include a description of what the PI will get post-correlation? I
>would hope that they would at least get all the calibration files with their
>data.
>
>Thanks,
>Jim
>
>--
>Dr Jim Lovell, Jim.Lovell_at_csiro.<!--nospam-->au
>CSIRO Australia Telescope National Facility Ph: (02) 6125 6715
>c/o RSAA, Mt Stromlo Observatory, Fax: (02) 6125 0260
>Cotter Road, Weston ACT 2611 Mobile: 0412 127364
>Australia http://www.atnf.csiro.au/people/Jim.Lovell
>At Tidbinbilla Ph (02) 6201 7842 (RA Lab), x7800 (switch), x7940(shift)
>
>
>
Received on 2006-06-02 10:02:46