CRIRES P2PP Tutorial

This tutorial provides a step-by-step example of the preparation of a set of Observation Blocks (OBs) with CRIRES, the cryogenic high-resolution infrared echelle spectrograph on UT1 (Antu) of the VLT. The specifics of this tutorial pertain to the preparation of OBs for Period 90 onwards. To follow it, you should have a P2PP (version 3) installation on your computer and be familiar with the essentials of the use of the software. Please refer to the instructions in order to install it, and to the P2PP3 User Manual for a general overview of P2PP3 and generic instructions on the preparation of Observing Blocks and scheduling containers.

0: Goal of the Run

In this tutorial we will prepare OBs for two simple example observing runs.

Case A consists of spectroscopy of a bright point source under good seeing conditions. Let's take the M-star AU Mic (RA (2000) = 20:45:09.5, Dec (2000) = -31:20:27) for which a high precision radial velocity shall be determined to search for faint companions. The target star also serves as Adaptive Optics (AO) guide star as well as the slit viewer (SV) guide star for fine guiding.

A telluric standard shall be observed right after the science target.

Case B describes the spectroscopy of a faint quasar for which no AO performance is needed but a nearby bright guide star is defined as reference target. Let's take for example the quasar HE 0251-5550 at redshift z>2 as target (RA (2000) = 02:52:40.1, Dec (2000) = -55:38:32) and a 11th magnitude star as guide star for this observation (RA (2000) = 02:52:37.24, Dec (2000) = -55:40:43.0, R=11.5). NaID and/or CaII H-K absorption lines shall be detected in the quasar's spectrum.

The sample OBs and scheduling containers used will illustrate the use of a variety of features of P2PP3 and illustrate the kind of decisions to be taken at the time of preparing in advance an observing run, as well as some aspects that are specific to the preparation of OBs for CRIRES.

1: Getting started

The Phase 2 process begins when you receive an email from ESO telling you that the allocation of time for the coming period has finalized and that you can view the results by logging into the User Portal and clicking on "Check the web letters." Note that the username and password that you need to use for the User Portal are the same as those you will use to prepare your OBs.

You follow the instructions given by ESO and find that time was allocated to your run with CRIRES. Therefore, you decide to start preparing your Phase 2 material.

First, you collect all the necessary documentation:

and you proceed with the installation of P2PP3 on your machine if necessary.

2: Case A: a bright star

You decide to start with the bright star as first science case. So, off you go to define those observations.

2.1: P2PP

For the sake of this tutorial, we will hereafter use the followingP2PP information:

  • P2PP ID: 52052
  • password: tutorial

This is a special account that ESO has set up so that users who do now have their own P2PP login data can still use P2PP and prepare example OBs. You cannot use it to prepare actual OBs intended to be executed.

After logging in using the tutorial account, the P2PP main GUI will appear as follows:

Click here to see the fullsize image.

Runs for a number of instruments appear as folders on the left, since the same tutorial account is used for all of them. Similarly, if you log in with your own P2PP ID, you will get the list of all the runs in which you are PI.

Select the folder corresponding to the CRIRES Tutorial run, 60.A-9253(K). In this tutorial we assume that time was allocated in Service Mode. This is indicated by the SM letters that appear next to the RunID of the CRIRES run.

You can now start defining your OBs. In this first case we want to take the telluric observation right after the science observation. Therefore, it is recommended to use the scheduling container 'Concatenation', symbolised by the violet 'C'-bullet in the icon menu on the top. When you click on this item a concatenation will be added under the CRIRES folder. You can give it a name by selecting the concatenation with the mouse and choosing 'Rename' in the menu of the right mouse button, or by using the 'File' menu on the top of the window and choosing 'Rename' there. Let's call the concatenation 'AU Mic 1'.

To create an OB under this concatenation, select the concatenation with the mouse and press the 'OB'-bullet in the icon menu on the top. You can rename the OB in the same manner as the concatenation. Since this OB will be the JHK observation of AU Mic, you can call the OB 'AU Mic JHK'. The red dot with the white cross 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.

To view and edit the OB press the 'Edit Observation Block' icon (pen with OB bullet) in the top icon menu. The OB window appears:

Click here to see the fullsize image.

This is the window where you will define the contents of your OB.

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2.2: Defining an OB

2.2.1: Filling in the Basic Information

Let this be the OB for spectroscopy in the J, H and K band of your bright star. It may be useful in many cases to have an easy way of identifying an observation description (OD), like when having observations of a number of targets performed with identical instrument configuration and exposure times. The OD Name field in the OB window allows you to define names for the ODs. The OD name appears in turn in the 'Obs/Clib Blocks' area of the P2PP main GUI, thus allowing the identification at a glance of all OBs having ODs with the same name. In this example OB, the OD will consist of a sequence of three spectroscopic exposures in the J, H, and K bands. We can thus appropriately name it 'JHK spectroscopy'. Enter this name in the OD Name field.

Next, the User Comments field can be used for any information you wish (to keep further track of the characteristics of the OB, to alert the staff on Paranal to special requirements. In particular, if a telluric standard has to be taken before or after this science OB you should write something like "The corresponding telluric OB is CAL_AU Mic JHK".

Finally, it is mandatory to use the Instrument Comments field for some information you have to pass to the staff on Paranal. In the case of CRIRES this is the expected signal-to-noise and magnitude of your target, and the magnitudes of the AO and SV guide stars. Since in this case the target also is the AO and SV guide star, simply enter "S/N=100@1580nm; J_OBJ=5.4; H_OBJ=4.8; K_OBJ=4.5".
Remember that the the S/N ratio should be given for the summed observations and not per one single DIT*NDIT exposure at one nodding/jitter position.

The entries then look like this:

Click here to see the fullsize image.

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2.2.2: Defining the acquisition template

The first template that must be part of any OB is the acquisition template, so let us define it next. In the Template Type list, make sure that the acquisition entry is selected. This will list the four acquisition templates available for CRIRES in the Template list.

After reading the description of the templates in the CRIRES User Manual, you have determined that the CRIRES_spec_acq_NGS template is the appropriate one for this observation because you want to use AO. You thus click on this template in the Template list, and then on the Add button next to it.

You need to decide now on the acquisition parameters. These are required for the pointing and tracking of the telescope, the centering of the target in the slit, the setting of the derotator mode, and for acquiring the natural guide star (NGS) and close the loop of the Adaptive Optics (AO) system.

Since your target also is the AO guide as well as SV guide star, the boxes Target = AO Guide Star and SV Guide Star = AO Guide Star should remain checked. The information for the AO guide star that has to be filled in is its B-R color. The color is needed to estimate the flux in R that reaches the wave front sensor (WFS) of the AO system. In the case of AU Mic, B-R = 2.36 (obtained from a Vizier query). The box Use the last sky measurement for the WFS should be unchecked if you are sure that there is no bright source at the default position of +4 arcsecs North and East of the target visible in the R-band. For very bright AO guide stars a sky measurement is recommended.

The parameters of the SV guide star and the telescope guide star should stay to their default values. Only for faint guide stars a new sky measurement for the SV is recommended (uncheck the box Use the last sky measurement for the SV in this case). The DIT and NDIT of the SV camera are determined automatically by the system.

We are coming to the point where some critical instrument parameters have to be set. Our target is a point source which can be observed using any orientation of the slit. In this case the derotator mode ELEV is recommended. In ELEV mode, the slit is constantly aligned with the parallactic angle in order to reduce slit loss introduced by differential refraction. This is important because the SV guiding will be performed in the J band whereas the observations are done in the J, H and K band. To select the ELEV mode, click on the red NODEFAULT field next to the Derotator: Mode box and select ELEV. The Position angle can, of course, not be chosen in this mode and stays at its default value 0.0. Next, the slit width and the wavelength range have to be chosen. Since we aim at the highest possible resolution the minimum slit width of 0.2 arcsec is appropriate. Let's assume that we like to cover the wavelength range 1235-1265 nm in the J band. The reference wavelength that corresponds to this wavelength range is 1254.4 nm (see Table 3 of the CRIRES User Manual). The grating order has only to be defined if the reference wavelength is not unique (see Table 6 of the CRIRES User Manual).

In summary, the set of parameters that you choose in your acquisition template is thus:

  • Detector Read-Out Mode: remains FowlerNsamp
  • Number of pixels aling Y axis: 64
  • Target = AO Guide Star: box remains checked
  • RA of AO guide star: Leave it to 0 (recommended) or enter 20:45:09.5
  • DEC of AO guide star: Leave it to 0 (recommended) or enter -31:20:27.0
  • AO guide star: B-R color value: 2.36
  • AO guide star: FWHM (arcsec): 0.0
  • AO guide star: Minimum S/N: 1000
  • Use the last sky measurement for the WFS: uncheck box
  • WFS Alpha sky offset (arcsec): 4.0
  • WFS Delta sky offset (arcsec): 4.0
  • SV Guide Star = AO Guide Star: box remains checked
  • Use the last sky measurement for the SV: box remains checked
  • RA offset to sky: 30.0
  • DEC offset to sky: 30.0
  • Telescope guide star selection: CATALOGUE
  • RA of telescope guide star: 0.0
  • DEC of telescope guide star: 0.0
  • RA offset between target and SV guide star: 0.0
  • DEC offset between target and SV guide star: 0.0
  • Derotator: Mode: ELEV
  • Position angle: 0.0
  • Entrance slit width: 0.2
  • Reference wavelength: 1254.4
  • Grating order: 0
  • Gas cell: remains FREE

The acquisition template is now complete, and the window should now look like this:

Click here to see the fullsize image.

2.2.3: Inserting Target Information

Let us for a moment take a break from inserting templates into this OB.

The coordinates (including epoch and equinox) of the science target have to be defined in the Target-tab. Just press the target icon in the icon menu on the top. There you can give the target the name "AU Mic" and should enter the target coordinates in the Right ascension and Declination boxes. Proper motions and differential tracking are not needed in our case. The only entry which may be edited is the Class to which this object belongs, for archival purposes. In this case, choose just Star.

After inserting the values the target-panel looks like this:

Click here to see the fullsize image.

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2.2.4: Setting the Constraint Set

As stated in Section 1, we assume for the purposes of this tutorial that the program has been allocated time in Service Mode. You thus need to specify a Constraint Set for your OBs. You can do this by clicking on the Constraint Set icon on the top icon menu and then filling the following entries:

  • First, 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 the spectroscopic observations, you type Spectroscopy constraints in the Name field.
  • Since you are not interested in achieving accurate flux calibration of your spectra, you request Variable, thin cirrus conditions in the Sky Transparency entry.
  • You like to have a very good AO performance. Therefore you should choose a good seeing. Enter 0.8 as value in the Seeing field.
  • Set the Airmass to 1.5, to ensure that your observations are not carried out at too low an elevation that would affect the AO performance.
  • Since you are doing high resolution spectroscopy of a bright target in the NIR, the lunar illumination has basically no influence. You should require 1.0 for the Lunar Illumination and 30 degrees for the Moon Angular Distance (smaller values might cause problems linked to the telescope guiding or AO system).
  • The Twilight constraint can be kept at 0 minutes. Observations in the H- and K-band might also be taken before the astronomical twilight ends (negative values), but since we have an J-band setting included it is safer to start the observations only when the astronomical twilight has ended.
  • The Strehl ratio defines the performance of the AO system, i.e. the ratio of the maximal intensity of the PSF to the maximal intensity expected for the theoretical PSF with no turbulence. This value is an output of the CRIRES Exposure Time Calculator (ETC). You always should enter the Strehl ratio in the K-band (also an ETC output), even though your spectra are taken in another band. In our case the K-band Strehl is 40.0%. Enter this in the Strehl (%) field.
  • Precipitable water vapour (PWV) influences the atmospheric water lines in particular beyond 2 microns. Since there will be a K-band setting in our OB, PWV should be set to a rather low value, let's say 3.5 mm.
  • The Atmospheric Turbulence Model can be set to default Paranal atmosphere model.

Your Constraint Set panel should look like this after entering the values:

Click here to see the fullsize image.

Note that in your Phase 1 proposal you already specified some of these constraints (seeing, lunar illumination, transparency). You must make sure that none of the constraints specified in Phase 2 is more stringent than the corresponding one specified at Phase 1.

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2.2.5: Setting the time intervals

We will assume now that the spectroscopic observations that you are defining are part of a spectroscopic monitoring program of AU Mic and that, to ensure that you have the spectroscopic shifts properly sampled, this particular OB needs to be executed at very specific dates during October and November. You can specify this under the Time Intervals tab, i.e. click the Time Intervals in the top icon menu, and then:

  • Click on the New TI button at the lower right . The pop-up window Add Time Interval will appear.
  • Modify the start and end UT times to define the first specific time interval when this OB shall be observed, in our case 2012-10-06, UT 12:00, and 2012-10-08, UT 12:00 for the start and end time, respectively.
  • Repeat the previous two steps to define all possible time intervals.

The panel looks like this now:

Click here to see the fullsize image.

You can edit or delite an already defined time interval by clicking on the blue bar of the respective time interval and then clicking on either the Edit or Delete button on the lower right.

If your observation have not to be observed at specific dates, but rather in equally spaced intervals, no matter when they are started, you might want to use a time time link container for the science OBs.

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2.2.6: Defining the Observation Description

Target, Constraint Set and Time Intervals are completed, the science template(s) can be inserted.

After checking with the manual and considering the scientific requirements of your program, you have decided to execute the observations using two nodding cycles (pattern ABBA) and jittering in a 5 arcsec box. The right template is the CRIRES_spec_obs_AutoNodOnSlit template. To select it, choose in the Template Type menu science. Then select the template and click on Add. The template will be attached to the grid below next to the acquisition template selected and filled previously.

Given the flux of your source and the advice on the duration of the individual DITs in each filter as given in the User Manual and checked with the Exposure Time Calculator (ETC), you decide that an appropriate choice of integration parameters is such that at each nodding position you obtain 15 exposures (NDIT) of 10 sec (DIT) in the J, H, and K band. A gas cell is not needed during the observations. Note that for CRIRES there is no need to submit a waiver request in case the OB contains multiple grating settings.

The first CRIRES_spec_obs_AutoNodOnSlit template (the observation in J) thus has the following parameters:

  • DIT: 10
  • NDIT: 15
  • Detector Read-Out Mode: FowlerNsamp
  • Number of exposures per nodding position: 1
  • Number of nodding cycles: 2
  • Nod throw along the slit: 10
  • Jitter width: 5
  • Reference wavelength: 1254.4
  • Grating order: 0
  • Gas cell: FREE

For the observations in the H and K band, we assume that the desired wavelength ranges are 1569-1609 nm and 2248-2292 nm, respectively. The corresponding reference wavelengths are 1595.0 and 2273.9 nm. Both wavelength settings are unique. No grating order has to be defined.You can select again the same template, Add it, and fill the parameters in the same way as done for the template in the J band. Alternatively, since the parameters of these other two templates will be very similar to those of the one just defined, you can speed up the preparation by clicking on any entry of the template for the J band (thereby selecting that column, it turns blue), then clicking twice on the Duplicate button on the right. In this way, you will have produced two identical copies of the first science template in which you should now only edit the parameters that change from template to template:

  • Reference wavelength must be changed to 1595.0 for the H band and 2273.9 for the K band.

The only other thing that you should really do at this point is to check the execution time for this OB. Press the Recalculate button next to the Execution Time label. The calculated OB execution time appears in the display to the right of the label. In this case the total execution time is 00:49:34, that is, well under the 1 hour execution time limit.

This completes your first OB! If you followed all the indications given so far, the OB window should look like this now:

Click here to see the fullsize image.

and you should see the OB named Au Mic JHK in the P2PP main GUI with the following contents in the Obs/Calib Blocks tab:

  • Local Id: 81 (in our case, can be any number)
  • Status: (P)artiallyDefined
  • Target: AU Mic
  • OD: JHK spectroscopy
  • CS: Spectroscopy constraints
  • Acquisition: CRIRES_spec_acq_NGS
  • FindingCharts: (0)
  • EphemerisFile:

You can reshape the columns as indicated in the P2PP User Manual to view the full contents of each entry.

You may have noticed the (0) under the heading ofFindingCharts. This is because you have not attached any Finding Charts to the OB. Following the general rules and CRIRES-specific rules for Finding Chart generation, you make your Finding Chart(s). The jpg file(s) should then be on your local disk, and you attach them one by one to the OB by highlighting the OB, clicking on the Finding Charts item on the top menu, and selecting Attach Finding Chart(s) from the pull-down menu. This gives you a browser window, in which you navigate to the correct directory and select the file(s). The P2PP Finding Chart Tutorial gives more advice on how to attach Finding Charts within P2PP.

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2.3: OB for telluric standard

The calibration plan does not include telluric standard star observations, so you decided to apply for time within your proposal to obtain an extra observation of this specific telluric star in JHKs. The telluric should ideally be close in RA and Dec to the science target, so that it can be observed at similar airmass. Now you must prepare the OB for this star. It was decided to have the telluric observations as part of a concatenation. So, highlight the 'Au Mic 1' concatenation ('C' icon) in the main P2PP GUI and click on the 'OB' icon in the top icon menu. A new OB appears under the concatenation.

Note that the naming of the telluric OB has to follow a certain rule. It has to start with the prefix CAL_. Ideally, after this prefix you repeat the name of science OB, i.e. in this case the telluric OB should be named CAL_AU Mic JHK. This makes it easier for the staff on Paranal to identify the association between science and telluric OBs.

In principle, this observation can be very similar to the JHKs jitter described in detail before. There is one very special difference, however. After having chosen and defined the acquisition template CRIRES_spec_acq_NGS you must choose in the Template Type menu calib. Then select the template CRIRES_spec_cal_AutoNodOnSlit and define the parameters as described above.

In the User Comments field you then should write something like "This OB should be observed after the science OB 'AU Mic JHK'.". Probably, the exposure time (DIT and NDIT) can be reduced since telluric stars normally are very bright. The time intervals do not have to be set since the science OBs take care of that in the framework of the concatenation. In this example we have chosen the star HIP 107380 as telluric.

This completes the definition of the first concatenation. The total execution time of a concatenation cannot exceed 1.5 hours. You can check that by highlighting the concatenation in the P2PP main GUI and choosing 'Execution Time' in the 'Report' menu on the top. A pop-up window will appear that summarizes the total execution time of the concatenation and their OBs.

Since in this example case, AU Mic should be observed at five different epochs, you need to create five concatenations. This can be best done by duplicating the existing concatenation. Highlight the concatenation 'AU Mic 1' and press the Duplicate icon in the top icon menu four times. You then can rename the four duplicated concatenations. In our case the structure of the CRIRES run looks then like this:

Click here to see the fullsize image.

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3: Case B: a faint target

When planning your second observing run, you realized that your spectroscopic target (the quasar) is too faint to serve as AO or SV guide star. Anyway, AO performance is not needed for this program and also the resolution can be quite moderate. A slit width of 0.4 arcsec would just do it to get enough flux and a seeing of 0.8 arcsec can be tolerated. No bright reference target is found within 40 arcsec of the science target. Thus no fine guiding with the SV can be performed. However, a quite bright star (R=11.5 mag) some 2.2 arcmin away from the quasar shall serve as telescope guide star. Note, however, that sources fainter than R=10.5 mag need sky conditions that are at least thin if not clear.

The interesting Na and Ca absorption lines are expected at 1967.5 and 1969.5 nm (Na) and 1314.0 and 1325.7 nm (Ca). These wavelengths can be covered by using three different wavelength settings in the H band. The total execution time per wavelength setting is expected to be of the order of 3 hours. So the different wavelength settings can not be put into one OB.

Most steps that you should follow to define the OB are analogous to those that you followed when preparing the AU Mic JHK OB before, although there are fewer parameters in the acquistion template this time.

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3.1: P2PP

It is assumed that you already started P2PP (version 3) and have chosen the CRIRES Tutorial run, 60.A-9253(K). If this is not the case please have a look at point 2.1.

If the absorption lines in one of the wavelength settings are more important than in another one, it might be a good idea to define a group container for each of the wavelength settings. For that highlight the folder of the CRIRES run and press the 'G'-bullet in the top icon menu. You might call the group 'HE 0251-5550 - Na'. Define an OB under this group by highlighting the group and clicking on the 'OB'-bullet in the top icon menu. Let's name this OB 'HE 0251-5550 - Na 1'. You can edit and view the OB by clicking on the 'Edit Observation Block' icon in the top icon menu.

3.1.1: Filling in the Basic Information

Let this be the OB for the Na lines around 1968 nm. The OD Name in this case could be H spectroscopy

The User Comments field and the Instrument Comments can/should be used. No information is needed in the User Comments for this OB (assuming that this observation does not need a telluric to be observed). In the Instrument Comments you should give the expected signal-to-noise and magnitude of you target. Enter "S/N=20@1968nm; H_OBJ=14.6".

The top of the OB window should now look like this:

Click here to see the fullsize image.

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3.1.2: Defining the acquisition template

The first template is the acquisition template. Since no AO is needed, the correct template is CRIRES_spec_acq_NoAO. Highlight this template and then click on the Add button next to it.

Although your target is faint you might try to use it as SV guide star. For this you should uncheck the Use the last sky measurement for the SV box to get a new sky measurement. For the Telescope guide star selection choose SETUPFILE from the pull-down menu. Then enter the coordinates of the guide star into thetelescope guide star boxes.

The Derotator: Mode should be set again to ELEV mode, Entrance slit width to 0.4 arcsec, and the Reference wavelength to 1984.3 nm.

The set of parameters that you choose in your acquisition template is thus:

  • Detector Read-Out Mode: FowlerNsamp
  • Number of pixles along Y axis: 64
  • Use the last sky measurement for the SV: uncheck box
  • RA offset to sky: 30.0
  • DEC offset to sky: 30.0
  • Telescope guide star selection: SETUPFILE
  • RA of telescope guide star: 02:52:37.24
  • DEC of telescope guide star: -55:40:43.0
  • RA offset between target and SV guide star: 0.0
  • DEC offset between target and SV guide star: 0.0
  • Derotator: Mode: ELEV
  • Position angle: 0.0
  • Entrance slit width: 0.4
  • Reference wavelength: 1984.3
  • Grating order: 0
  • Gas cell: FREE

The acquisition template is now complete, and the window should now look like this:

Click here to see the fullsize image.

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3.1.3: Inserting Target Information

Press the 'Target' icon on the top icon menu in the OB window. You can give the target the name "HE 0251-5550" and should enter the target coordinates in the Right ascension and Declination boxes. Proper motions and differential tracking are not needed in our case. The only entry which may be edited is the Class to which this object belongs, for archival purposes. In this case, choose DLy-alpha_ALS for a damped Lyman alpha system.

After inserting the values the sub-panel looks like this:

Click here to see the fullsize image.

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3.1.4: Setting the Constraint Set

We again assume for the purposes of this tutorial that the program has been allocated time in Service Mode. You thus need to specify a Constraint Set for your OBs. You can do this by clicking on the Constraint Set icon and filling the entries under it:

  • First, give a descriptive name to the constraint set about to be defined. For example, type Quasar spectroscopy constraints in the Name field.
  • Since you are not interested in achieving accurate flux calibration of your spectra, you request Variable, thin cirrus conditions in the Sky Transparency entry. Due to the faintness of the target and SV guide star thick conditions would probabaly lead to troubles for proper guiding.
  • Very good seeing is not needed. 0.8 arcsec should be sufficient to get enough flux into the 0.4 arcsec slit. Enter 0.8 as value in the Seeing field.
  • The Airmass might be set to 2.0, since no AO is needed.
  • Since you are doing high resolution spectroscopy of a target in the NIR, the lunar illumination has very little influence. You should require 1.0 for the Lunar Illumination and 30 degrees for the Moon Angular Distance (smaller values might cause problems linked to the telescope guiding).
  • The Twilight constraint can be set to -30 minutes, since observations in the H-band are not affected by the astronomical twilight.
  • The Strehl ratio does not apply since no AO is requested. It should be left to the default value 0.0.
  • Precipitable water vapour (PWV) is not that critical at the observed wavelength. PWV can be set to a moderate value, let's say 10 mm.
  • The Atmospheric Turbulence Model does not amtter and can be kept at no constraint.

Your Constraint Set panel should look like this after entering the values:

Click here to see the fullsize image.

Note that in your Phase 1 proposal you already specified some of these constraints (seeing, lunar illumination, transparency). You must make sure that none of the constraints specified in Phase 2 is more stringent than the corresponding one specified at Phase 1.

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3.1.5: Setting the time intervals

This time no time constraints are needed. No values have to be entered.

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3.1.6: Defining the Observation Description

Once the acquisition and the items Target and Constraint Set are completed, the science template(s) can be inserted in the Observation Description.

The faint target needs long exposure times. After consulting the exposure time calculator you find that DITs of 300 sec and a NDIT of 12 is needed to reach the desired signal-to-noise. One nodding cycle (AB) is sufficient to handle the sky subtraction, but at each nodding position the exposures shall be jittered in a 5 arcsec box. Thus a DIT of 300 sec, a NDIT of 2 and 3 as Number of exposures per nodding position is chosen as observing strategy. No gas cell is needed for this observation.

Again, the only template to choose is the CRIRES_spec_obs_AutoNodOnSlit template from the 'Template Type' 'science'. This time it should have the following parameters:

  • DIT: 300
  • NDIT: 2
  • Detector Read-Out Mode: FowlerNsamp
  • Number of pixles along Y axis: 64
  • Number of exposures per nodding position: 3
  • Number of nodding cycles: 1
  • Nod throw along the slit: 10
  • Jitter width: 5
  • Reference wavelength: 1984.3
  • Grating order: 0
  • Gas cell: FREE

When checking the Execution Time by clicking the Recalculate button, you notice that the execution time for this OB is 1:15:49 hours, still longer than the allowed 1-hour. Either your scientific justification for such a long OB is very strong and you decide to try getting approval for this through a Waiver Request, or you feel that you can simply divide this OB into two smaller ones (with smaller DITs and/or NDITs) to achieve the same scientific goal(s).

This completes your first OB of your second run! If you followed all the indications given so far, the View OB window should look like this now:

Click here to see the fullsize image.

and you should see the OB named HE 0251-5550 - Na 1 in the P2PP main GUI with the following contents in the Obs/Calib Blocks tab:

  • Local Id: 234 (in our case, can be any number)
  • Status: (P)artiallyDefined
  • Target: HE 0251-5550
  • OD: H spectroscopy
  • CS: Quasar spectroscopy constraints
  • Acquisition: CRIRES_spec_acq_NoAO
  • FindingCharts: (0)
  • EphemerisFile:

You can reshape the columns as indicated in the P2PP User Manual to view the full contents of each entry. Finding Chart generation and attachment to the OB can be done as described in Case A

To complete your second run you have to define further OBs for the wavelength settings with the Ca lines. The reference wavelengths are 1318.1 and 1330.0 nm for the lines at 1314.0 and 1325.7 nm, respectively. The ETC tells you that for this regions a NDIT of 48 is needed for the same DIT of 300 sec as for the previous OB. Thus four 1:15:49 hours OBs have to be defined for each of the wavelength settings. For that you can create two further group containers. To make life easier, you decide to simply duplicate the previously made group (HE 0251-5550 - Na 1) twice and use the copies as a starting point. To do this select the appropriate group in the P2PP main GUI and press the Duplicate icon in the top icon menu. You can rename the two newly created groups to 'HE 0251-5550 - Na 1314' and 'HE 0251-5550 - Na 1326', for example. The same you can do for the OBs under the new groups. Then highlight one of those OBs and press the Edit Observation Block icon, and you can change the relevant parameter(s) (Reference wavelength, DIT, NDIT, etc.) in the science template. In total, 9 OBs in three groups are necessary to defime the second run. Just duplicate the newly defined OBs in both groups there times each. Let's hope that your waivers about the long execution time are successful!

The structure of the CRIRES run in the P2PP main GUI looks then like this:

 

Click here to see the fullsize image.

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4: Finishing the preparation and submitting the OBs

Another view of the observing run structure is the Schedule view. In the P2PP main GUI click on the tab Schedule below the icon menu. The CRIRES runs should then look like this:

Click here to see the fullsize image.

In this view you can assign priorities to the containers or single OBs. You can choose numbers between 1 and 10. The lower the number the higher the priority of the group. In our case we chose the group for the Na line to have higher priority (priority = 1) than the two groups with the Ca lines (priorities 2 and 3). Within the groups you could give the individual OBs a different weight (called 'group contribution'). Since all OBs in our groups are identical this makes no sense in our cases.

With the completion of the OBs for case A and B, we consider the examples developed in this tutorial to be finished.

We will now submit these OBs to the ESO Database: highlight all the containers, go to the File menu in the P2PP main GUI, and select the Check-in option. A dialog box will appear asking for confirmation and, if you click on OK or Yes, they will be saved in the ESO Database.

At this point, for the case of a real Service Mode Run only you should click on the Whistle-icon on the upper right of the top icon menu. This has the effect of sending a signal email to your Support Scientist that OBs have been checked into the ESO Repository.

Again for the case of a real Service Mode Run only you should also view/edit/check-in a corresponding README file. For that you have to use the View / Edit Readme icon in the top icon menu. A special tutorial is avaioable for the Readme file.

As a courtesy to the next user who follows this tutorial, we would like to ask you to finish these exercises by removing the OBs form the ESO Database. The P2PP User Manual gives you detailed indications on how to do this. In short,

  • Select Check-out... from the File menu in P2PP
  • In the Database Browser window that opens, type 60.A-9253(K) in the Prog ID selection criterion
  • Click on the Query button on the lower left
  • Select all the OBs that appear in the display area after the query. Normally there should be your submitted OBs only, but if another user has submitted other OBs from this same account without removing them afterward you will see them as well.
  • Under the File menu in the View OB window, select Check-out

In this way the OBs will be removed from the ESO Database and will beleft in your Local Cache only. From there you can delete them if you like by selecting them and choosing the Delete option under the File menu in the P2PP main GUI.

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Instrument selector