Spigot obs with Astrid
Most of an email from Scott Ransom giving an introduction to using the Spigot with Astrid.
See also this web page
for full-blown command-line spigot instructions.
Date: Wed, 9 Nov 2005 15:48:47 -0500
From: Scott Ransom
Subject: Astrid Intro
Resent-Date: Thu, 10 Nov 2005 14:49:25 -0500
Hey All,
OK. So here is a limited intro to Astrid for you. I would recommend
the following.
- Quickly read the following two web pages to get acquainted with what
Astrid is all about:
http://wiki.gb.nrao.edu/bin/view/Data/AstronomersIntegratedDesktop
http://wiki.gb.nrao.edu/bin/view/Software/ObservingTools
- Login to a GB machine via VNC and take a look at some of my Spigot
scheduling blocks and play around with the interface a bit (see below).
Here is what I would do for #2:
- Login to GB (ssh.gb.nrao.edu) and then to titania or naiad (those are
the observing machines). If you are not observing I would recommend
naiad since that machine is not used as often for real observing).
- From that machine start:
vncserver -depth 8 geometry 1200x900
(feel free to edit the depth and geometry)
- Then on your home machine run:
vncviewer -via [your username]@ssh.gb.nrao.edu titania:1
(or whatever the display number is).
- Modern (2006): Run ~sransom/bin/myastrid to get paths set up right when starting astrid.
Historical (2005): From there, in some terminal, do the following assuming that bash is
your shell (just to be safe):
export PYTHONPATH=
export PGPLOT_DEV=
export PGPLOT_DIR=
export LD_LIBRARYPATH=
These are currently needed in case your environment has PRESTO
capability. PRESTO uses a different version of PGPLOT than astrid's
graphical display, and astrid will SEGFAULT if it gets the wrong one
during the AutoPeak() scan. Then start astrid (it is called astrid) from that window.
- For now,
select the "work-offline" mode. You would choose one of the other
modes if you were actually going to observe (and had been placed in the
"gateway" by the operator). You can change your mode later from the
File->"Real Time Mode" menu option.
- In the main window, select the "Edit" tab and choose project GBT05C-042.
You can click on each of the various scheduling blocks that are
displayed and they will show up in the editor window. I've labeled
them with A*, B*, C* etc to show you the way that you would submit them
during an real observation. So take a look at them in that order.
- In general, for a simple Spigot-based pulsar observation we do:
- Slew to a test pulsar
- Perform an AutoPeakFocus() which will determine pointing and focus
corrections with respect to the currently used pointing model of the
telescope based on scans on a nearby (to the test pulsar) continuum
calibrator. This scan is useful for L-band and higher frequency (skip
it for prime focus). When you run this in real-life the DataDisplay
tab will show you plots of the scans and after 4 of them (for pointing)
are done, you will see a set of corrections in Az and El (daz, del) in
arcmin. Those values should almost always be a small fraction of an
arcmin. If they are not, there is probably a problem with the pointing
model (talk to the operator). You will also get rough values for the
system temperature.
- Slew back to the test pulsar
- Balance the system (Note: for prime focus work you also need to
specifically focus the PF1 receiver. See the "*balance" scheduling
blocks for GBT05C-045 for an example of that.) Make sure that the
levels are OK and the spectrometer duty cycles are ~0.8. See my old
notes for details.
- Start the autoleveler (_outside_ of astrid as per the old spigot
notes).
- Configure the system for Spigot (or BCPM+Spigot, or Spigot+GASP)
usage.
- Setup the spigot (for this you need to specify a data directory on
the spigot2 machine. NOTE: this directory should _not_ already exist.
Astrid will create it for you. If you want to create it yourself, make
sure that its permissions are 1777).
- Take a short test scan and then fold it on the spigot2 machine with
prepfold.
- Slew to your science source and balance the IFRack (and PF1
receiver if necessary).
- Take science data.
- For multiple scans using user generated catalogs etc, check out the
"spigot_dosurvey" scheduling block in project GBT05C-045
You can submit several scheduling blocks in a row and Astrid will queue
them up and execute them when they are ready. In general, you should
watch the status of things in a different terminal using the
"gbtstatus" command.
You can also switch back and forth between the "Edit" and "Run" tabs if
you need to change a scheduling block or two. Scheduling blocks can be
copied between projects and they can be imported/exported as text files
as well. They can use pretty much any legal python in them (and there
are lots of modules available as well). Hit the "Validate" button to
check your syntax before saving. One last thing to mention is that you
have to make sure to enter your name as the Observer and the telescope
operator's name in the Operator space before you submit your first
scheduling block.
Feel free to poke around and look at scheduling blocks from other
proposals as well. Toney Minter has some pretty sophisticated
scheduling blocks in GBT05C-049 that show user defined scan types and
how to import special python libraries.
Let me know if you have any questions,
Scott
Ingrid Stairs
Last modified: Mon Jul 31 18:36:22 PDT 2006