CRIRES p2 Tutorial

This tutorial provides guidelines on how to prepare a set of Observation Blocks (OBs) with CRIRES, the CRyogenic high-resolution InfraRed Echelle Spectrograph on UT3 of the VLT. The specifics of this tutorial pertain to the preparation of OBs for Period 108 onwards.

To follow this tutorial you should have familiarity with p2: the web-based tool for the preparation of Phase 2 materials. A short introductiory video illustrating how to use p2 is available here.

Please refer to the main p2 webpage (and the items in the menu bar on the left of that page) for a general overview of p2 and generic instructions on the preparation of Observing Blocks (OB). Please also follow the link to the p2 ObsPrep Tutorial for explanations on what can be done with the ObsPrep tab of p2, including (not applicable in P108: interactive planning of blind offset and observing offsets (e.g., generic offsets, nod-on-slit),) uploading of user provided background images which are also used to create the instrument-compliant Finding Charts with the p2fc Tab (see here). 

Screenshots for the tutorials were made using the demo mode of p2, but should not differ in any way from one's experience in preparing your own OBs under your run.

Quick overview of general CRIRES observing concept

Observations at the VLT are performed in terms of Observing Block (OB), which represents the basic observational unit. As such, astronomers specify their programmes in terms of OBs, which contain all the necessary information to obtain a single observation. Observations with CRIRES are therefore performed through dedicated OBs that contain both general and CRIRES specific information. In what follows we concentrate on the main CRIRES specific information required to construct an OB, while for a quick summary of the general ESO Phase 2 material (i.e. details of the OB that are not instrument dependent) we refer the reader to this page.

    Observations with CRIRES in P108 can be performed in the following modes:

  • no AO assisted spectroscopy with Target = Slit Viewer Guide Star

    Slit = 0.2 / 0.4 '', different wavelength settings, Target / Slit viewer guide stars must be in the brightness range 0 ≤H≤14.5

  • AO assisted spectroscopy with Target = Natural Guide Star = Slit Viewer Guide Star

    Slit  = 0.2 / 0.4", different wavelength settings, Target / NGS / SVGS cannot be brighter than R=0.2 mag and must be brighter than R = 14 mag. Observations using NGS stars with 14 < R < 15 must have a turbulence category of 10% in both the Phase 1 proposal and in the OB.

  • Not offered in P108: spectro-polarimetry, offset acquisition or observations, spectro-astrometry

    These mode are still being commissioned, and could be offered in future periods

In your proposal you have already indicated the mode, and the time you need to fulfill your science goal. This was done by consulting the CRIRES User Manual and the Exposure Time Calculator.

The following links provide an OB preparation tutorial for a variety of science cases requiring diffent observing strategy and instrument setup:


By logging into the p2 demo, under the programme ID 60.A-9253(K) you can access to the USD-Tutorials folder where we have stored a sample of OBs designed for different modes and observing strategy. The example OBs are not editable but can be exported if needed. Please refrain from creating new OBs in the USD-Tutorials folder.


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