[daip] questions about using and getting help with AIPS

[Ray Lucas]

Hi,

This email is addressed to both daip at nrao.edu and to Dr. Lorent
Sjouwerman since I am not sure which one is the most appropriate
one to receive these questions. (My last question has to do with
a VLA pipeline.) If it is more appropriate for the other to reply,
my apologies to the one I should not have bothered! In any case,
I am not sure who is the "designated AIP" at the moment as per
the web page at http://www.aoc.nrao.edu/aips/d_aip.html, but I
wanted to make sure that both are aware in case a response has
to be coordinated, or in case the daip address is no longer used,
etc. (Its last update seems to have been in 2004.) Anyway, my
apologies if this email should have been directed elsewhere!
;-)

I have a NVO program to reduce some old VLA data that I took
in 1990 (yes, that long ago - but its a long story - basically
life intervened!) and incorporate it into a new NVO-compliant
database of multiwavelength images and parameters, etc.

The program was a continuum snapshot program of about 70+
Texas interferometer steep-spectrum sources and several
standard VLA calibrator sources mixed in, and the data were
taken in A-array configuration. My VLA program in 1990 was
AL218, and I was the PI. I recently requested the data (I
don't remember whether I requested it in the "original" or
newer "AIPS Friendly" style since it has taken me longer to
get back to this in recent weeks than I intended) and
received it via ftp, but I have not yet tried the task FILLM
or done anything with it. As I understand it, the new format
is supposed to help more with keeping track of the files more
simply by project name, etc. Perhaps I should re-retrieve
the data soon, being sure to request the new "AIPS-friendly"
version just in case I requested the original style before,
though I suspect I would have requested the new style, anyway.
In fact, while typing in this email, I have just re-requested
it in the AIPS-friendly format, so now I'll know that I have
the new versions.

I've asked our computer folks to install a recent version of
AIPS here, and they've taken their shot at it. I think it is
one of the last two versions or so, but not absolutely sure
without checking some more with them or searching for the
details myself, or trying to start it up and seeing if I'm
getting the proper new version or an older one that was in
place before it. There is someone here who may have some
experience with using AIPS, but I'm not sure how much or how
recent that experience may be.

So, I've been looking through some documentation - the AIPS
Cookbook and some various pages on task descriptions, etc.
and the pages on "who to call or email - the "daips" page"
and VLA Contacts page - and I have a few questions initially.

1)
If I decide I need some direct help, i.e. need to go to one
of the NRAO facilities and work directly and closely with
someone who knows what they're doing and can give me expert
and frequent assistance or step through the process with me,
it sounds as if I could go to Charlottesville, which is much
closer for me, but that there is no real local support there
other than making sure that the software is working, and that
the system is really geared towards having me come out to
Socorro for that kind of more labor-intensive or maybe even
collaborative help. Is that still correct? (I have no problem
with Socorro - I enjoyed my visit there when I came to take
the data back in 1990 - its just that Charlottesville is much
closer and I can drive there in about 3 hours for the cost of
a tank of gas in my car...!)

2)
In looking at various tasks and reading about them, I see
that the task SCMAP seems to be the preferred one for making
the uv maps, and that MAPIT is described as being inferior
to SCMAP in general, but that it is particularly suited to
snapshot observations. So, I'm not quite clear on this. Is
SCMAP or MAPIT the preferred option for reducing/making the
uv maps from the snapshot observations if one wants to make
the data as good as possible (or at least as good as is
"reasonably" possible!) I would like to make these uv maps be
as high quality as I can, but don't want to go too far past
the point of diminishing returns to the point that I'm putting
in a lot of extra effort for very minimal increase in quality,
unless there is something in particular that seems especially
worth it, perhaps even to be done in a separate and later
reduction after the first basic one is done, if that seems an
advantageous way to do it, though if possible, I'd also like
to just do the best job all at once and be done with it.
Anyway, I'd appreciate an expert's opinion and advice on
the best thing to do here in terms of which would be the best
way to proceed, and also on which would be the best task to
use in this kind of case, which may have some higher-than-normal
profile given that it may be used in a kind of NVO prototype.)

3)
Is there a sort of detailed (but still somewhat high-level)
step-wise procedure documented for making uv maps from snapshots
in the preferred manner (i.e. that best combination of quality
and reasonable level of effort that I'm talking about)? It may
just be that I've somehow overlooked it, but I haven't managed
to find something like that yet. (The AIPS Cookbook Table of
Contents provides clues somewhat like this, I guess, but its
still not the thing in exactly the format I'm really wanting to
find.)

4)
I also see from the "Contact Info for VLA" web page that there
is a VLA pipeline. I had only seen something about VLBA pipeline
before... Does this mean that there may be a standard pipeline
for processing my data now, producing output products that are
calibrated uv maps of my sources from the snapshot observations?
If so, where can I find out more about this? And may I use it?
If like some other standard data pipelines, I can understand that
it might have some limitations which, if one wants the very best
output and end data products, might necessitate re-running with
more tweaks or updates or more manual intervention, but it would
still be an interesting/nice idea for at least a starting point...
(For this reason, I am cc'ing Lorant Sjouwerman at the VLA AOC
as well as daips at nrao.org, as per the VLA Contact Info Web Page.)

Thanks very much in advance for your help and advice!

Best regards,
Ray Lucas
(STScI, Baltimore)