ALFALFA Survey - Setup and Observing Cookbook

WARNING: Version date: September 2012
Cookbook date: 3 Sep 2012
CIMA version : "The Stable version (Default) (Ver.3.3.02 2012-06-07 17:14)"
WAPPdata : /share/pserverf.sdb1/wappdata/         (a2010 alias is "wdata2")

This has not been fully updated for the Fall 2012 season; for now, it has the general details, but please check the checklist for specifics.


Find the 2007 version here, the Spring 2008 version here, the Fall 2008 version here and the Spring 2009 version here. The special version used in March-April 2010 is here. The special zenith strip observing for Fall 2010 instructions are here. The normal transit mode observing instruction for Fall 2010 are here and for Fall 2011 here.

IMPORTANT NOTES FOR Sep-Oct 2012

  • All beams are reported functioning; look for updates after we start observing Sep 10th.
  • Note: Warnings about WAPP chip count errors appear in the cimalog file (but not in the CIMA log window). Examples are:
    • "WAPP=4-chip_count: Counts don't match between chip 0 and chip 4 (99999964 != 99999966 diff = 2)!"
    • "WAPPDATA-search_agc: Interpolating agc-data over 2.00 second time gap (65545.0 - 65547.0)!"
    • "WARNING WAPPDATA-search_pnt: WARNING extrapolating pnt-data from 55592.243889 to 55592.243900!" As long as the "diff" is small or the interpolation is over only a few secs or the extrapolation is likewise small, there is no real problem. Just check the data, both in the waterfall plots and using "quicklook".
  • While these CIMA warnings are not fatal, they make the cimalog files large (Mbytes). If size of the cimalog file exceeds the limit of the web service, you may not be able to view it. Be sure to include the link in the loglinks file anyway. And, of course, keep an eye on the WAPPS for more serious **error** messages.
  • Note:   Sept 12, 2010:     The TOGS calibration script sometimes hangs at the stage of rotating ALFA into position and times out (after 2 min). Run it again, and it should work. The problem has been reported. We have not seen this for a while, so we hope the problem has been fixed.
  • In Fall 2012, we will be completing the on-meridian drifts of the northernmost ALFALFA tile so that all the observing will be at Az = 180 (or 540 if that is nearer). or a2010, you need to use the a2010_az180_2012.conf configuration file; the azimuth can be either 180 or 540; pick the one nearer to the current position.
  • In Fall 2012, TOGS runs at the START (so start observing 15 min before the posted time for A2010). Be sure that the DecJ of galfasrc in the a2010.cat file is set to the same DecJ as tonight's drift. Load the TOGS command file: command_galfasrc.cmd.
    If there are problems running TOGS, please call Snez (work: 608 890 1458 or home: 608 259 9449) to let her know (but don't delay the start of A2010; you can always call her later).
  • We position the telescope at a particular Az (on the meridian) and DecJ2000. Always double check that the DecJ2000 is correct by checking that the "Rslt" declination in the monpnt display is the correct DecJ2000. It will be updated every ten minutes (beginning of each drift), so it may stray a bit, and it may require a few seconds to move into position. Remember that that the beam is ~3.5 arcmin and it takes ~14 sec of time for a source to drift through the beam so if you are "off source" for a few seconds at the start of the next drift, it doesn't really matter....
  • The ALFA rotation angle for meridian observing is 19 degrees. This is set properly when you load the configuration file.
  • You need to start CIMA by typing "cima --X". (Notice the "--X".)
  • "Help" info is available by right clicking on any widget or parameter
  • The sources in your catalog which are "visible" are indicated along with their current location, slew time, etc.
  • It is possible to launch the system monitoring widgets from within CIMA.
  • "Accept" is the same as "Apply"+"Dismiss"
  • The scan number convention is "ydddNNNNN.fits" where "y" is the year number, "ddd" is the day number within the year and "NNNNN" is a sequential number which now has nothing to do with the time. Note also it has nothing to do with the FITS file number.


Disclaimer: CIMA changes, conditions change, and we have to adapt to situations as they develop; this cookbook works today but may not tomorrow! In particular, we are using the latest released CIMA version, called the "The Stable version (Default) (Ver.3.3.02 2012-06-07 17:14)". Please read the documentation on the CIMA website. If you want to experiment with CIMA offline, be careful not to overwrite or change the observing files!

Before Observing

TOGS GALFA setup - the operator will carry out this step.

Datataking

Beginning Observations:

  • Ending the Observations
  • Recovering from WAPP errors


    Data Monitoring

    Mikael has developed a great package for telescope monitoring and data display. These programs read the data that are being broadcasted to the FITS files, and not the FITS files themselves. The screens are updated every 10 seconds.
    On Dataview, click on the background and select from the menu: You can open the same widgets by typing on an xterm on a linux machine: Note: you can now pull up many of these widgets from CIMA buttons directly. See the CIMA website for other cool widgets developed by Mikael.

    The program alfadatawin is currently only available on Linux machines. The other commands are available on other machines, too. Notice that you will not be able to start alfadatawin if the process is already running on dataview (started by one of the previous observers). If this happens, ask the telescope operator to contact Mikael, Arun, or Phil to kill the previous process(es).

    Notes

    Log files

    It is very important to keep an accurate log of what happens, even to note "an uneventful night". To do so:


    After Observing

    After the run has finished, do the following things to keep the rest of the a2010 group informed about how the run is going.

    Reading Data into IDL and saving to Disk

    Once a observing session is complete, all the FITS files can be converted into a set of IDL structures for future use; ask Brian about any details about this. It is probably best to do this at your "office" workstation at AO, and run the job on one of the fusion machines. Below, IDL> means "inside idl".

    Useful Links


    This page is maintained by the members of the Cornell ExtraGalactic Group and their ALFALFA team friends
    Last updated Thu Sep 6 15:37:56 EDT 2012 by martha