JCMT OT Tricks

This tutorial covers a few aspects of advanced usage of the JCMT Observing Tool (OT). It is assumed that you are already familiar with the OT, or have completed the “JCMT OT Basics” tutorial. For further information, you may wish to refer to the following documentation:

To complete this tutorial, you will need to download and unpack the example files.

The package includes a completed version of each example science program which you can compare with your solution.

1. Simplifying programs with inheritance

This example features a simple but very repetitive science program. The aim is simplify the program by reducing the amount of duplicate information.

  1. Open the 1_inheritance_example.xml file.

  2. Take a look through the structure of this science program. You should notice that:

  3. Remember that when an item is present at one level in a science program tree, it applies to everything at lower levels. So we can move the common items to the top level rather than duplicating them in each MSB.

    There are two ways you can move an item:

    If you choose to move an item by dragging it, you will notice the icon of the target location change as follows:

    Down-pointing arrow
    The item will be moved below the target location.
    Diagonal downwards arrow
    The item will be moved inside the target location. If instead you wished to move it below the target, move the pointer further to the left.
    Red circle with ×-mark
    This indicates that the item can not be moved here.

    Go ahead and move the “SCUBA-2” item to the top level of the program, just above the first MSB.

  4. Now that you have SCUBA-2 at the top level, you don't need to repeat it in all the other MSBs. Select this item in each MSB and use the “Cut” button in the tool bar to remove it.

  5. You can repeat this procedure for the other duplicate items, such as the notes and the “Site Quality” and “DRRecipe” components.

  6. Imagine that you want to add something special to the notes for just one of the MSBs. Initially this might seem a problem, since we have a single note for all of them!

    However the OMP will combine multiple notes when someone views your MSBs. Therefore we can simply add a new note to one of the MSBs and put just the extra information there.

    Try adding an extra note to one of the MSBs. Don’t forget to check the “Show to the Observer” box so that the note is shown at the telescope.

2. Organizing MSBs in “and” folders

“And” folders are used to group a collection of MSBs together. The most common uses for them are organizing a program and applying common settings to a number of MSBs. When used in these ways, “and” folders do not affect the observation of MSBs inside — they are still each done individually.

  1. Open the 2_and_example.xml file. This is a science program containing a few MSBs based on the JCMT calibration program’s spectral line standards for HARP.

  2. Note how several common items are located at the top level so that they apply to all MSBs:

    However the targets, receiver tuning information and in some cases observing mode differ between the MSBs. Also the “DRRecipe” components are placed next to the “Het Setup” components because the OT needs to know which instrument is being used when configuring DR recipe choices.

  3. We can organize this program by making an “and” folder for each molecular line being observed.

  4. Move each MSB to the corresponding folder. You can do this either by dragging them and dropping them inside, or by cutting and pasting them.

    You should end up with the two C18O 3–2 MSBs in one folder and the two HCN 4–3 MSBs in the other.

    The science program is already more organized than it was before. If the program had a large number of MSBs, then the ability to open and close folders as a whole would be very useful. Note that making this change does not alter how the program will be observed — each MSB is still observed individually.

  5. Finally we can use inheritance to avoid having duplicate tuning information for each set of MSBs:

3. Using survey containers

Survey containers allow you to repeat an MSB for multiple targets. In this example we will construct a SCUBA-2 daisy observation in a survey container.

  1. Create a new science program.

  2. Fill in the identifying information for the top level science program item.

  3. Add a survey container to the program by clicking this entry in the item panel at the left of the window.

    For now, we will ignore the survey container itself and prepare our MSB.

  4. With the survey container item selected in the program tree panel, click the “MSB Folder” button in the item panel.

    This should add an MSB which is nested inside the survey container. If it was added in the wrong position, drag the MSB in the tree panel and drop it inside the survey container. (When dragging an item inside another item, you should see an arrow pointing diagonally down and right. If instead you see a plain downward pointing arrow — indicating that the item will be moved below the target — move the pointer further to the right.)

    Alternative: instead of constructing an MSB manually you could copy one from the SCUBA-2 library and remove the target information component. Then skip the next step.

  5. Set up the MSB as a SCUBA-2 daisy map observation. Add the following items to your MSB:

    Note that no target information component is required since we are using a survey container to provide target information.

  6. Select the observation item and note the estimated time of 31 minutes — this is our 1800 second integration time with some allowance for observing overheads.

  7. Next we will set up the target list in the survey container itself. Begin by selecting this item in the program tree panel.

    The easiest way to fill the target list is to load coordinates from a text file. Click the “Load” button at the bottom of the panel and open the 3_messier_galaxies.txt file.

    The initial default position of 0:00:00 0:00:00 will still be present at the top of the survey container. Select this entry and click the “Remove” button to delete it.

    Note how the observations remaining counter values and priorities have also been loaded from the text file. You can alter these values by selecting a target and using the controls at the bottom of the panel.

  8. It is also possible to edit survey container targets directly in the OT. You can do this by selecting one of the targets and then clicking the “Target Information” tab at the top of the panel. This opens a similar interface to that used to configure an individual target. Targets can have reference positions here when necessary. Click the “Survey Targets” tab to return to the list.

  9. Finally select the MSB item in the program tree and check the estimated time. Even though we have 20 targets with 5 repeats each, the time to perform the MSB should be 31 minutes — the same as the observation inside.

    If instead we had set this program up with the survey container inside the MSB, that would indicate that everything had to be done in a single session. If the science program is arranged in this manner you will find that the time for the MSB is over 52 hours! This is clearly not what we want in this case.

4. Understanding validation results

This example is intended to allow you to practice working through the output of the OT’s validation tool. A science program with a number of intentional errors is provided.

  1. Open the 4_validation_example.xml file.

  2. Select one of the MSBs in the program and press the “Validation” button in the window toolbar.

    Note how the OT shows just the internal check results for the selected MSB.

  3. Select the main science program item (labeled “Problematic Program”) and press the “Validation” button.

    Note now the OT now shows internal check results for all MSBs and the XML schema validation results.

  4. Try to adjust the program to correct the problems identified by the validator.

    We recommend that you work on one MSB at a time, validating that individual MSB. Afterwards you should validate the program as a whole.

  5. Can you see any more problems with this program that the validator does not find?