- Ask the Operator if you have control of the telescope
You should do this at every telescope...
- Ask the Operator to turn off the TV monitor cameras (so that it no
longer shows the receiver floor). This prevents some potential RFI.
- 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.
- 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
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.
- 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.
Figure 6: Screen shot of the main AO-Control and the calibration windows seen by the observer.
- 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
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.
- 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)
Figure 7: Screen shot of the catalog and visible sources widgets.
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 ``#''.
- Click ``Visible Sources'' and choose the source you wish to observe
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
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.
- 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.
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
- 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
(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
- Choose the sampling level and polarization(s) for this board from
the pull-down menu (Figure 11).
- 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
both your dump time and 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 seconds the correlator will take data every minutes.
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
- Do you want to use Circular or Linear polarization (the default is circular)
- Which 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
- At this point it is strongly advised that you save your current set up
- FINALLY - Click ``Observe'' and start taking data
- 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.