The Details

1. Log-in to the data taking computer using the log-in name and password provided by the on-duty telescope Operator.

2. Ask the Operator if you have control of the telescope
   You should do this at every telescope...

3. Ask the Operator to turn off the TV monitor cameras (so that it no longer shows the receiver floor). This prevents some potential RFI.

4. 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.
   
   Screen shot of the main AO--Control Startup screen as seen by the observer.

5. 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
   ``! /share/obs4/usr/a9999 does not exist''
   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.
   
   Choosing the receiver and IFLO configuration.

6. Choose the receiver/IFLO set-up you wish to use
   At this point you must choose which receiver and IF set-up you wish to use. Chances are that you will wish to use a Gregorian receiver with a standard IFLO path. That is, you want to choose a receiver from the "Standard Observing" list which is not part of the Carriage house (Figure 4).

   The "Non-standard" heading provides a list of both receivers which are still being tested (e.g. receiver has not yet been available long enough for a full pointing model to have been developed) and it lists non-standard configurations for the receivers. As an example. Figure 4 has listed the "L-band Wide, 1-2Ghz IF". Opting for this choice would provide you with the L-band wide receiver, but your signal would get sent through the 1-2GHz down-converter instead of the usual 750MHz down-converter.

   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.

   
   Screen shot of the main AO--Control and the calibration windows seen by the observer.

7. Click ``Calibrate'' to run a calibration scan or two
   The AO-Control Main Window should now appear (Figure 5) 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 on 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 5). 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 at your observing frequencies with a well known, non-variable flux density. Sources with ``good" in the source list are believed to have well-known, non variable flux densities. Additionally, if no size is listed after the source, it is believed to be $<15^{\prime\prime}$ in size.

   After the cross scans are complete, a window will appear which shows the results of fitting Carl Heiles' Mueller Matrix routine to the data (Figure 5). With this you can check not only the beam's 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.

8. 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 go to the next step. If it is not, click on ``Catalog'' to bring up a window listing all the catalogs available.
   
   Screen shot of the catalog and visible sources widgets.
   
   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 7 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 ``#''.

9. 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. 6) will appear. For each source this widget lists the name, approximate Azimuth and Zenith Angles, the remaining time for which you can observe this source today, and any comments you have entered. Sources just about to rise above the telescope 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 §1.10.3 if you want to disable this safety feature), AO-Control will point the telescope to your source, and begin tracking it.

10. 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. 8.
    
    The initial appearance of the spectral line observer's widget

    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 setting your observing parameters, choosing a different observing procedure causes the parameters to be deleted!)

11. 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 files (.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.)

    • Click ``New Setup'' to get access to the set up for your first correlator board.
    • Enter the center frequency for the 1st board in the box provided This can be the rest frequency or the observed frequency. If you plan on observing one of the standard spectral lines, you can simply click on the ``Board 1'' button to get a list of commonly observed lines. Double clicking on any of these lines will enter that rest frequency into the frequency box Figure 9.
      
      The standard astronomical lines widget

    • Choose the sampling level and polarization(s) for this board from the pull-down menu (Figure 10).
      The pull-down menu for setting the sampling levels & board polarization

    • Choose the bandwidth for this board from the pull-down menu.
    • Choose the number of lags/subcorrelator you wish to use from the pull-down menu.

      NOTE: The sampling level, bandwidth, and number of lags/subcorrelator are closely interconnected. As a result, if you wish to have, i.e. 50-MHz bandwidth you cannot have 9-level sampling. So to get the 50-MHz option you must first choose a 3-level sampling option. A table describing all the allowed options is given in the Appendices.

    • Assuming you want more than one correlator board (there are four independent boards available for use), you can now either click on ``Next Board'' or ``Copy Board'' to enable you to enter the information for the next board. Repeat this process until you've set up all the boards you wish to use.

    • You must now decide how long an integration time to use. This is the total integrated time for each data record, and is the indivisible time unit in which your data will be taken. The standard units (1s, 6s, 10s, 30s, & 60s) are given in a pull-down menu. You can obtain a non-standard setting by clicking on the ``Advanced Options'' button and changing either your dump time and/or your total number of cycles/integration (these multiply together to give you your total integration time).

      The ``Advanced Correlator Options'' widget also allows you to set when the correlator begins taking data. I.e. if you set this to 10 seconds, the correlator will begin taking data only when the time is at a interval divisible by ten seconds, e.g. 12:01:00, 12:01:10, 12:01:20, whereas if you set this to 1 second the correlator will take data every second. The default value is 1 second.

    • If you're using the L-wide receiver (and only if you're using the L-wide receiver), you must now make the following choices:
      • Do you want to use Circular or Linear polarization (the default is circular)
      • Which r.f. filter do you want to use? The ranges available for each filter can be found by clicking on the red numbers after ``Filterbank''. You can also choose to let AO-Control choose the filter for you. This means you're letting AO-Control decide the optimum filter for your use. Note that if you choose this option, be sure that the frequency at which you observe (the redshifted frequency) falls within the chosen filter.

    • At this point you need make choices based on the observing procedure which you chose. These choices are carefully outlined in Section 1.3.

12. At this point it is strongly advised that you save your current set up

13. FINALLY - Click ``Observe'' and start taking data

14. 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.