The Details next up previous contents
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The Details

  1. Ask the Operator if you have control of the telescope
    You should do this at every telescope...
  2. Ask the Operator to turn off the TV monitor cameras (so that it no longer shows the receiver floor). This prevents some potential RFI.
  3. Type ``gui'' (in the data-taking window)
    This will start up the AO-Control GUI. When you're actually starting observing, this command is traditionally typed in the ``data-taking'' window at the lower left of the data-taking computer's monitor. You can run the gui on any computer logged into the Arecibo system, but the telescope commands are only implemented when you are logged into the data-taking computer. NOTE: This means you should not run the gui on the data taking computer unless you are in control of the telescope. On the other hand, the off-line version of the gui conveniently lets you create your set-up files off line and save them, making your start-up time minimal when you get on the telescope.

      figure368

  4. Enter your name and proposal i.d. Click ``Line''
    Figure 3 shows the AO-Control Startup window. If you do not enter the correct proposal id, your log and data files will be named incorrectly. This is BAD. If you enter the incorrect proposal id, and/or have a nonstandard file area (this holds mostly for AO staff), you will get a message saying

    At this point (assuming your proposal i.d. is entered correctly and you simply have a nonstandard file area), you simply need to enter the correct path to your file area in the ``Default working directory'' box that appears.

      figure381

      figure390

  5. Choose ``Gregorian Dome'' and then pick the receiver you wish to use
    At this point you must choose which receiver you wish to use. All standard receivers for spectral line work are contained within the Gregorian Dome. So first you must choose the Gregorian as your master feed, and then choose the receiver you wish to use (Figures 4, 5). For a list of available receivers, frequencies, and sensitivities, see the above section on Receivers (Section 1.2) or go to http://www.naic.edu/techinfo/teltech/upgrade/rec.htm.

      figure376
    Figure 6: Screen shot of the main AO-Control and the calibration windows seen by the observer.  

  6. Click ``Calibrate'' to run a calibration scan or two
    The AO-Control Main Window should now appear (Figure 6) As you are at the beginning of your run, it is a good idea to run a calibration scan or two to check that the telescope is behaving properly. To do this, simply click in the ``Calibrate'' button in the AO-Control Main Window. A new window will then appear with a list of the calibration sources currently visible to the Arecibo sky (Figure 6). Once you choose a source from this list (by double clicking on the source name), the telescope will perform a spider scan on that source, process the data, and give you the results. The source you choose should, ideally, be a point source with a well known and non-variable flux density. Sources with ``good" in the source list are believed to have a well-known, non variable flux densities. Additionally, if no size is listed after the source, it is believed to be 15'' in size.

    After the cross scans are complete, a window will appear which shows the results of fitting Carl Heiles' Muller Matrix routine to the data (Figure 6). With this you can check not only the beams shape, but also the system temperature, the side-lobe size and pattern, the system gain (in K/Jy), and even the determined source polarization.

    Like all telescope calibration, it is a good idea to run this procedure a few times on a few different sources during your run.

  7. Click ``Catalog'' to choose your source catalog (Main Window)
    To expedite your observing, the next step is to choose the first object in your observing program, and then start the telescope slewing. First, you need to choose your source catalog. If there is a file in your current (working) directory called ``src.list,'' AO-Control will assume this is the source list you wish to use. If it is, life is fine and just got to the next step. If it is not, click on ``Catalog'' to bring up a window listing all the catalogs (files ending in ``.list'' in your working directory)

      figure387
    Figure 7: Screen shot of the catalog and visible sources widgets.  

      figure392
    Figure 8: Setting the coordinates for your object.  

    If you do not have a working catalog, you can create one by clicking on ``Set Coordinates'' This will pop up a widget (Figure 8 which asks you for the source name, coordinates, etc. and then (assuming your write permissions are set correctly) enters this information into a file called ``src.list'' in your working directory. Similarly, if the object you wish to observe is not in a catalog, using the ``Set Coordinates'' button will append the entered object into your src.list catalog. You can now bypass the next step by simply clicking ``point'', thereby telling the telescope to slew to your object and begin tracking it. Note that if you wish to enter a velocity for your source in the ``Set Coordinates'' window, you do so by entering the velocity in the ``Comment'' section of that window. True comments should be preceded by a ``#''.

  8. Click ``Visible Sources'' and choose the source you wish to observe
    (Main Window)

    You can now choose your first program source. You should do this as soon as possible to give the telescope time to slew. Choosing a source is done by clicking ``Visible Sources'' in the Main Window. This causes AO-Control to grab the current catalog file, and determine the current positions of the sources visible at the current local sidereal time.

    After a few seconds, the visible source widget (Fig. 7) will appear. For each source this widget lists the name, approximate Azimuth and Zenith Angles, the remaining time (today) to observe this source during today, and any comments you have entered. Sources just about to rise above the telescope azimuth and zenith angle limit are also displayed. Double clicking on a line containing the source you want to point at will initiate a pointing command. Following a yes/no confirmation that you really want to track this source, (see §1.9.3 if you want to disable this feature), AO-Control will point the telescope to your source, and begin tracking it.

  9. Choose your observing procedure (``Standard On/Off'', ``Drift Map", etc.) Once you've selected a receiver, the line observing widget will appear on the screen. Initially, it will look like the widget shown in Fig. 9.

      figure429

    The first thing you want to do is to choose your observing procedure. (As different procedures have different parameters, you could become frustrated when, after carefully choosing your observing parameters, choosing a different observing procedure causes the parameters to be deleted!)

  10. Choose your set-up...
    You now need to set-up the correlator. The easiest way to do this is to load a pre-existing file. This can either be a file you created off line (and then moved into your working directory on the data-taking computer (being sure to give read/write/execute permission to the world so the gui can read and write to it), or it can be one of the ``standard'' set-up files listed in the Appendices. If you wish to load a standard set-up, click on "Load Standard" and a list of the standard spectral line set-up files will appear. If you wish to choose a file which exists in your working directory, just click on ``Load Setup'', which will display all spectral line set up (.sls) files in your working directory. Assuming the set up you want is available, just double click on it and it will automatically be loaded into the Spectral Line Observer's Widget.

    If the file you want doesn't already exist, you need to follow the steps below. (Note - you can also use the following steps to modify a currently existing set up, after loading it into the gui - just replace the ``New Setup'' line below with one of the ``Load'' steps above.)

  11. At this point it is strongly advised that you save your current set up
  12. FINALLY - Click ``Observe'' and start taking data
  13. When you're done for the day, be sure to click ``Exit VX-Works'' to exit AO-Control and move your data.

    Your data will then be moved to ``/share/olcor/corfile.<date>.<proj>.#'' where <date> is the current date (i.e. 13 March, 2000 is 13mar00); <proj> is your project i.d. (i.e. a9999); # guarantees your data file will have a unique number by incrementing this number every time you invoke the ``mvdata'' command. So if this is the second time you've moved the data today (12 January, 2000) for your project (a9999), your data will be moved to: /share/olcor/corfile.12jan00.a9999.2.


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Next: Useful Stuff Up: THE SOURCE LIST Previous: A Quick Look

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