How to prepare GROUP containers
This tutorial provides a step-by-step example of the preparation of a group scheduling container, one of the new features of P2PP version 3. To follow the tutorial you should have a P2PP installation on your computer and be familiar with the essentials of the use of P2PP (version 3). Please refer to the P2PP Webpage for detailed installation instructions, the latest P2PP version to be used, and to the P2PP User Manual for a general overview of P2PP and generic instructions on the preparation of Observing Blocks.
Because the scope of this tutorial is to show how to prepare a GROUP container in general, it is meant to be instrument independent hence it will not give you a detailed description on how to make an OB for a given instrument. Specifically devoted tutorial for each VLT instruments can be found in the Service Mode guidelines Webpage, under the Manuals and Tutorials tab section.
What is a group container?
A group container is a simple collection of OBs that may be executed independently of each other in any order. Once you place the OBs in a group and one of them is executed then the remaining OBs belonging to the group will be executed preferentially before any other part of the programme.
The use of group containers may be envisaged by the following examples:
- The observing programme contains several targets located very close to each other on the sky, and for each target more than one OB is needed. If possible, you want that all observations of a single target are completed before a new target observation is started. This can be achieved by creating a group containing all the OBs for a given target.
- The observing programme contains a target observed repeatedly through many different setups (i.e. filters/grisms). If possible, you want that all observations for a given setup are executed before starting a new one. This can be achieved by creating a group containing all the OBs for a given setup.
Your goal here is to observe with SINFONI two different targets located very close to each other on the sky. For each target you will use the same grating (i.e. K) but two spatial resolutions (i.e. 250 and 100 mas scale). After checking the Exposure Time Calculator you find out that, for a given target and setup, you need 40min of integration time on source, which can be split in two OBs. For each target we will hence prepare a group containing 4 OBs because you prefer that all observations of a given source are completed before a new target observation is started.
We assume that you have started the P2PP session, logged in and selected the run within the P2PP main GUI for which the OBs should be prepared. For the sake of this tutorial we will use the P2PP special tutorial account that ESO has set up so that users who do not have their own P2PP login data can still use P2PP and prepare example OBs. You cannot use this account to prepare actual OBs intended to be executed.
After starting P2PP and logging in using the tutorial account (i.e. login: 52052, password: tutorial), the P2PP main GUI will appear as follows:
In what follows we will create first a group container and then we will proceed to fill the container with OBs. However, it might be the case that you have already prepared some OBs and only after that you realize that the observing strategy would benefit if you group them together in a group container. In this case you can skip what follows below and jump directly here.
The first step now is to create a group which will contain all the OBs for a given target. To do so click on the G green icon on the upper bar of the P2PP main GUI. This creates an entry under the Observing Runs area that look like as follow:
Next step is naming the group and because there is no special requirement on the group's name we will call it target1. Select the group with the mouse, press Enter and type target1 in the New Group field. The P2PP main GUI should then appear as follows:
To create an OB within the group target1, click on the OB blue icon on the upper left side of the P2PP main GUI. This creates an entry under the Observing Runs area. The red dot next to the OB name means that the OB fails to pass some fundamental verification criteria, as may be expected from the fact that no template has been attached to the OB yet. Because in this tutorial we decided that the first OB is meant to use the grating K with the 250 mas scale we will name it 250-K1. To name the OB, as done previously in case of the group container, select the OB, press Enter and type 250-K1 in the field No Name. At this point your P2PP main GUI looks like the figure here below:
Double click on the OB name to have access to the main OB window where you define the contents of your OB. Because this OB will define spectroscopic observations with the grating K and 250 mas plate scale, we decide to name the Observing Description as 250-K. Thus type 250-K in the OD Name field.
The first template that must be part of any science OB is the acquisition template, so now you need to choose it and specify the appropriate parameters. In the Template Type list make sure that the acquisition entry is selected. This will list all the acquisition templates available for SINFONI in the Template list below to it. In this example, our SINFONI observations are in NGS mode. target1 will be used as NGS itself so you type its coordinates in the RA of AO Guide Star and DEC of AO Guide Star fields, and its R magnitude and B-R color in the R mag of AO Guide Star and NGS B-R Color fields, respectively. You then select from a pull down menu next to field SPAXEL size (arcsec) the 0.25 scale, and the grating K for the Instrument setup name. Finally, your decision for the values of DIT and NDIT depends on the brightness of the target. Since we assume here that target1 is fairly bright and easily identifiable in a short exposure of 5 seconds long, you type 5 in the DIT field and 1 for the NDIT. You can then leave the remaining parameters to their Default values.
At this point the OB main GUI should appear as follows:
Now it is time to insert the science template. On Template Type, select now science and the existing SINFONI science templates will appear. In this tutorial we will use the SINFONI_ifs_img_FixedSkyOffset template that allows you to nod between the target and a given empty region on the sky, which in this example is located 79 and -9 arcsec away towards E-S. Select the aforementioned template from the list and then click on the Add button on the right side. After consulting the Exposure Time Calculator you decide to use a DIT of 300 sec, NDIT of 1 and 4 AB cycles. The science template has thus the following parameters:
- Integration time (DIT): 300
- Observation Category: SCIENCE (Default)
- Jitter box width: 1
- Nuber of AB or BA cycles: 4
- NDIT for the OBJECT position: 1
- NDIT for the SKY position: 1
- Number of exposures per offset position:1
- Alpha offset to sky: 79
- Delta offset to sky: -9
- Spectral dithering (T/F):unchecked (i.e. False) Spectral dithering is not offered
- SPAXEL size (arcsec): 0.25
- Instrument setup name: K
The OB main window should look like this:
To access the view window where you should provide the Target information click on the Target icon in the top left of the main OB window. There you can start by filling in the available fields with the appropriate parameters. Here insert the target name, which could be the same name as used for the OB itself. In other words, insert Name:target1. Also, enter the right ascension and declination for target1.
- Right Ascension:10:20:30
Furthermore, edit the entry in the target-tabbed subpanel Class. In our case, choose Radio for Radio galaxy. All other target related fields can be left at their default values.
The new OB GUI should appear as follows:
We assume for the purpose of this tutorial that the program has been allocated time in Service Mode. You thus need to specify a set of constraints, which indicate under which conditions your OB can be executed. You can do this by clicking on the Constraint Set icon which will give you access to the view window.
Now you should fill all the entries specific to SINFONI observations (i.e. only 7 entries)
Name: give a descriptive name to the constraint set about to be defined. Since you have decided that this constraint set will be applied to all K observations with the 250 mas scale, you type 250Kin the Name field.
Sky transparency: your observation can be performed with rather loose constraints, hence you request Variable, thin cirrus conditions in the Sky Transparency entry.
Seeing: you specify 0.8 as the value of the Seeing field.
Airmass: set the airmass to 1.6 to ensure that your observations are not carried out at too low elevation.
Lunar illumination and Moon Angular Distance: since you are doing broad band observations in the near-infrared, the lunar illumination has very little influence. You can thus leave the default values of 1.0 and 30 degrees for the Lunar Illumination and Moon Angular Distance fields.
Strehl (%) - AO only: Here you type the value you have obtained when you have simulated this observation with the Exposure Time Calculator. In this case you type 33
NOTE: In your Phase I proposal you already specified some of these constraints (lunar phase, seeing, and transparency). At Phase II, you can relax your constraints to improve the chances of execution of your programme, but you cannot specify more stringent constraints.
The Constraint Set view window should now appear as follows:
In this example we are not going to use any time interval constraints. The user interested in setting a time interval to a given OB can refer to the instrument P2PP tutorials.
As mentioned in section 0, in this tutorial we want to create for a given target 4 OBs with 2 setups, and the faster way to proceed is to duplicate the OB we have just prepared and then edit only the parameters that changes from OB to OB. To duplicate the OB, go back to the P2PP main GUI, select the OB 250-K1 and then click three times on the green arrow icon on the upper bar. This will create 3 new OBs named 250-K1_2, 250-K1_3, 250-K1_4 , which are identical copies of the 250-K1 OB.
As done in section 3 you then rename the last 2 OBs as 100-K1 and 100-K1_2 (to highlight the use of a different setup, for instance), then as in section 3.4 you update the constraints window, this time requesting a seeing of 0.6". Finally, as done in sections 3.1 and 3.2 in the acquisition and science template you select 0.1 in the SPAXEL size (arcsec) field.
If you have followed all the indications given so far, the P2PP main GUI should look like this:
As mentioned in section 0, in this tutorial we intend to create 2 groups of OBs for two different targets. Now, because the observing setup and strategy (i.e. grating, spaxel scale, exposure time) will not vary from target to target, then the easiest way to create a group for the second target is to duplicate the existing container and then changing only the relevant fields.
To duplicate a group, in the P2PP main GUI select the group target1 and then click on the green arrow icon in the upper bar. As shown in the picture below, this will automatically duplicate the selected group and will crate a second identical named target1_2.
Now we will modify the first OB of the new group with the relevant information for target2. As done in section 3.3, double click on the OB name to access to the Target window and fill the relevant fields, namely the Name, the Right Ascension, and the Declination. Assuming that this new target is called target2 and it is located at RA=10:20:30 and DEC=-29:50:03, then the Target main window should look like as follows:
As done in section 3.1, we now edit the relevant fields in the OB acquisition template for this new target. The target coordinates, NGS R magnitude and B-R color should then be provided in the acquisition template. Assuming that target2 is also used as NGS and that its R magnitude is 12 and its (B-R) color is -1.6, then the Observing Description window should appear as below:
Now we need to update the remaining 3 OBs (250-K2, 100_K1 and 100-K2) with the target2 information. One can either repeat what has been just done in case of OB 250-K1 or, to be faster, the relevant fields can be copied from OB 250-K1 and then pasted into the remaining 3 OBs. To do so, select the OB from which you want to copy the information (i.e. 250-K1 in this case), click on the right mouse button to have access to a pull-down menu as shown below. Then select OB Properties and choose Copy Target option.
Select the remaining three OBs (250-K2, 100-K1, 100-K2) and click on the right mouse button to have access to the pull down menu, as done previously. Select again OB Properties and now choose the option Paste to selected OBs. See below
Now, we need to copy from OB 250-K1 the acquisition template and then paste it to the other 3 OBs, as just done for the Target information. Once you have done, the four OBs should then share exactly the same acquisition template and Target information and the P2PP main GUI should appear as follows:
Groups have an overall priority, which is similar to an OB user priority in the case of independent OBs. In addition, to every OB belonging to a group is given a group contribution value, indicating how much the overall group score is increased by successfully executing that given OB. Once the observations of a given group have started, the group score is increased, thereby increasing the priority of all the OBs in that group, with respect to other independent OBs, or with respect to other scheduling containers that may have the same OB user priority or container user priority. As shown in the picture below, by looking at the P2PP main GUI under the Schedule tab one can notice that currently both groups have priority 1 and that all OBs share the same group contribution (i.e. 10).
In this tutorial we decide to request that OBs for target1 are executed prior those for target2, hence we assign a higher priority to the group named target1. To do so, select with the mouse the GROUP named target2 and then click on the number displayed under the group Priority column. The group priority, as that for independent OB, is a number ranging from 1 to 10, where 1 corresponds to the highest priority. Type 2 in the priority column of group target2 to give an higher priority to target1.
Finally, in this example we also want that observations using the 100mas scale should be completed before those designed with the 250mas scale. We can do it by changing the OB contribution value which is a number ranging from 1 to 100, where 100 is the highest contribution. For all OBs named 100-K1 and 100-K2, we then type 100 under the Contrib. to Group column, while 50 for the OBs named 250-K1 and 250-K2.
If you have followed all the instructions given so far the P2PP main GUI should appear as follows:
With the priorities and group's contribution assignment we consider the example developped in this tutorial finished.
However, if you are interested in a comprehensive explanation on how attach finding charts, edit and submit README file, as well as submit final sets of OBs and containers you should have a look at this page.
Here we assume that you have already prepared 4 independent OBs to observe the same target (i.e. target1) with the 250mas and 100mas plate scales. Your P2PP main GUI will look then like as follows:
Now you realize that your observing strategy would benefit from having these four OBs scheduled within a GROUP container. The quicker way to proceed is hence to create a new empty group container. You click on the G green icon on the upper bar of the P2PP main GUI.
The P2PP main GUI appears as follows:
Now to fill the New Group container with the OBs you have already prepared, with the mouse you can select them and then drag them into the group. If you have done so, then in the P2PP main GUI now the OBs appear directly under the group container as shown here below:
Note that by dragging the OBs within a group container the OBs get automatically a default value (i.e. 10) for the group's contribution. From now on you can refer to section 5 for further information about the group's priority and OBs groups contribution.
With the completion of the group we consider this tutorial to be finished. However, the Phase 2 package preparation is completed only after providing the finding charts and the README file. The reader can refer to the following pages for a more detailed description of the final three steps:
Click here to return to the general P2PP documentation page.
- 0: Goal of the Run
- 1: Getting Started
- 2: Create a group
- 3: Define an OB within a group
- 4: Modifying groups
- 5: groups priority
- 6: Adding OBs into a group container
- 7: README, Finding Chart and Package Submission