A3341 Observing Checklist (for APPSS SEARCH MODE LBW Observations)

Version date: September 2019
Checklist date: September 11, 2019
CIMA version : "The Stable version (Default) (Ver 3.3.13 2014-05-08 17:14)"

Before observing, be sure to study the background document. And, if you are not familiar with it, review the description of the WAPP SEARCH mode.

If the CIMA version/time stamp is not as appears above (one or the other has changed a few times in the last week), check the CIMA User's Log to see what has happened. Presumably any changes made would not apply to us; don't take the adjective "stable" too literally.

This is a short checklist of the things to do when observing with LBW as part of the ALFALFA followup observations.
Remote observers: see the LBW remote observing checklist (Note: instructions are almost the same as for A2010/ALFA except of course when it comes to the specifics).
It is always a good idea to check with recent observers about their experiences.

Important points about ALFALFA followup observing with LBW
  1. 2019:   From some sites, it will be better to use ssh -Y rather than ssh -X. Both commands enable X11 forwarding and require X11 security extension restrictions, but the -Y option enables trusted X11 forwardings rather than extension controls. NEW! IMPORTANT! .
  2. 2019:   If you have connected remotely to remoteATnaicDOTedu previously and before Oct 27, 2016, you will not be able to log in to that machine until you fix its host key on the machine you used to connect. Look here for how to perform the fix. NEW! IMPORTANT! .
  3. 2019:   Most programs do not run on remote; after logging in on that machine, you need to then log in to another AO machine before starting up aostatus, monpnt, etc. NEW! IMPORTANT! .
  4. 2019:   READ THIS! IT IS IMPORTANT   Because of upgrades to AO machines, we have run into issues with VNC connections, particularly on dataview. See one of the two bullets below depending on your operating system. Be sure to test VNC well before your observing run! First test VNC on one of the machines used for reduction; then test on dataview DURING A MAINTENANCE PERIOD when observations are not being conducted.
    • For linux users, David Craig has written a useful document on VNC connections.
    • Sometimes users of either linux or Mac have run into some weird stuff described here by Jeff Miller.
    • Mac users may experience some "issues" trying to run VNC on the new incarnation of the machine called "dataview". See notes here!
  5. Oct 2016!   Ignore the message "wappdata getting low on disk space" if it appears in the CIMA log window. Nothing to worry about.
  6. For data monitoring/reduction, use one of the machines: aserv11, aserv21 or galfas1 rather than fusion00 (or one of the decomissioned aolcNs).
  7. For the APPSS, we will be using the WAPP spectrometer in a staggered, overlapping frequency band mode to search for HI signals from galaxies whose redshifts we do not know. In this "WAPP-search" mode, each of the 4 WAPP boards is set to observe both polarizatiopns of a 25 MHz bandpass with each board centered on a different frequency (instead of the whole 100 MHz ALFALFA frequency range). Be sure to understand the ALFALFA team WAPP search spectrometer mode. In previous LBW observations we used the interim correlator at specified velocity; you can find the instructions for that mode here .
  8. The disk location of the WAPP data was changed on 25 August 2015. The physical location is now called /share/wappdata.now. You can find ALL of the wappdata for this and older programs via the symbolic link /share/wappdata; there is no need to remember the different "pserver" disk allocations.
  9. Don't forget to RESTART THE WAPPS at startup, before you load the configuration file.   For some of us, this is blast from the past: "When in doubt, restart the WAPPs!"
  10. Sometimes it happens that one of the WAPP boards is bad. Be sure you know what to do if that is the case; see the discussion below on what to do while observing.
  11. In 2019, the configuation file will be the same every night; only the command file containing the observing sequence will change. See the A2010 schedule page.
  12. We still use the a2010 user account (to login, etc), but the observing program name is different. In fall 2019, the observing program is called "a3341". You can navigate, as user a2010, to the observing file directory by typing "a3341obs" in any window.
  13. We use LBW (the L-band wide receiver).
  14. We use the idl_lbw software routines to monitor the data. There are different subpackages depending on whether you are looking at correlator (ICORR) data or WAPP search data. You'll have to follow the instructions; see below!
  15. The observing sequence is executed using a command file. Once you set up the receiver and the correlator and start to run the command file, the observing sequence will run automatically, moving from source to source and running the ON-OFF sequence for each one smoothly (but again, you need to pay attention!).
  16. The observing program for a3341 consists normally of a series of 5-minute ON-OFF "pairs", one for each galaxy followed automatically by a CalON/CalOFF sequence which takes 20 seconds; observing each target "pair" takes about 13 minutes plus slew time. Then it's time to look at the resulting spectrum to see if there is a galaxy lurking there!   Note: Sometimes observations only last 3 minutes (if the source name does not start with "S".
  17. During each observing block, the observing sequence will be executed by running a command file called "a3341_YYMMDD.cmd", found in the observing directory "/share/obs4/usr/a3341". We also use only one configuration file: a3341.conf.
  18. Additionally, in the "/share/obs4/usr/a3341/oct19" directory, you will find two other files for your use:
    • a3341logYYMMDD: a template log file for the night. Please fill in/correct as necessary. Be sure to look at some old log files for examples, e.g. one example
    • a3341_YYMMDD_nominal.txt: an approximate schedule for the night. Notice that the times here are ONLY APPROXIMATE and that the given azimuths are for the source not the dome.
  19. NOTE THIS!!!!   If there is any chance of rain or fog, ask the operator to disable the tiedowns. In March 2013, bad baselines occurred when there was some rain and/or fog because one or more of the distomats was not recording. The symptom: bad baselines with 1 MHz periodicity. Solution: disable the tiedowns. If unsure, discuss with the operator, but we are thinking that the best solution is simply to disable them. Read Phil's explanation here.
  20. Your job includes (a) watching that the telescope does what it is supposed to; (b) making sure the timing of the observations stays roughly on schedule; and (c) making a quick check of the result for each galaxy to see if there is a detection; hence you will have to keep track of what is going on!


While Observing:

Finishing up:

After observing...

Here, we're assuming the date is Oct 11, 2016 and the observing block therefore is 16.10.11. Change as necessary.

Open a terminal on an Arecibo machine (i.e. remote.naic.edu):

This page maintained by the members of the Cornell ExtraGalactic Group and their friends, the other members of the ALFALFA observing team
Last modified: Fri Oct 11 10:43:22 EDT 2019 by martha