README File description

The README file contains an overview of the run, aspects specific to it, and an instrument-dependent checklist. The README file interface is accessible from the p2 interface via the Readme button. The README file has the following sections:

  • A non-editable section giving basic information on the run as scheduled: the program ID and type (normal, large, guaranteed time, or director's discretionary time), instrument, PI name, priority class, and approved execution time.
  • A list of sections accessible through tabs where specific aspects of the run can be described:
    • General Description: a short and concise summary of the observation, providing the night astronomer with any information needed to meet your science objective (e.g. SNR). Decision paths and/or OB modification requests that depend on the outcome of previously executed OBs are not allowed.
    • Waiver Requests: a short summary of any approved Phase 2 waiver requests, including when they were submitted and when they were approved.
    • Critical Observing Conditions Constraints: any information about required observing conditions other than those defined in the Constraints Set box that are critical for the achievement of the goals of the project.
    • Time-Critical Aspects: any information on timing of the observations including a brief reference to parameters of time-link OB containers, if used, or absolute time intervals, if defined in the OBs.
    • Special Execution Requirements: any specific information regarding the execution of your observation such as on proper target identification or details on the execution procedure.
    • Special Calibration Information: if you have submitted OBs for calibration, please describe them here, why you have submitted them, and how they should be executed relative to your science OBs (e.g. same night, once per observing run, etc.), unless included in an OB concatenation. In particular, for some instruments, you must provide the magnitude and spectral type for all user supplied photometric or spectrophotometric calibration stars.
    • ToO Information: please indicate here if this is a Target of Opportunity run and give any special details.
    • ToO Activators List: please give here the names and e-mail addresses of the investigators who are authorized to trigger a Target of Opportunity observation.
    • Pre-Imaging Requirements: if this is a pre-imaging run, please indicate it here and describe any special requirements; for instance the need to obtain on- and off- observations in narrow-band filters contiguously.
  • An entry for the e-mail address of the Principal Investigator of the programme. This information is taken from the User Portal.
  • Estimated Total Execution Time: please include here the execution time as given by the execution time report of P2PP.
  • Is this a Pre-imaging run? this is a tick box that must be checked if the run is pre-imaging for another run. This is important to ensure that pre-imaging runs receive the correct execution priority.
  • In case pre-imaging was required to prepare these OBs, you must indicate the source of pre-imaging in the corresponding box. If the source is none of those listed there, you can indicate the actual source in the entry below it.

The last part of the README file is a check list including most of the relevant aspects related to Phase 2 preparation with the corresponding instrument. You must click either yes or N/A (in case the question is Not Applicable) to ensure that you have taken all these aspects into account.

Additional Contents for the NACO README file

In addition to the general requirements for README FILES, the following NAOS-CONICA specific recommendations should be followed:

  • The magnitude of the brightest object in all fields (at or near the wavelength of the observation), including standard stars, must be specified.
    • If the brightness exceeds those cited below, full justification must be supplied.
  • For NGS OBs the type of wavefront sensor used and the magnitude of the AO reference star (at the appropriate wavelength) must be specified.

Observational Brightness Limits

Observations involving fields with objects brighter than those specifed in the table below cannot be guaranteed. Requests for observations not compliant with these limits must be submitted as a Phase 2 Waiver Request.

Mode Magnitude Limit
SW broad band imaging 6
SW narrow band imaging 4
LW broad band imaging 5
LW narrow band imaging 3
spectroscopy 2

If the neutral density filters are used, subtract 4 magnitudes. NOTE: Spectroscopic observations with the ND filters are not supported.

If the N90C10 dichroic is used, subtract 3 magnitudes.

OBs that require maximum field rotation with pupil tracking

NACO users with OBs that require maximum field rotation are required to specify LST ranges in their OBs.  These LST time ranges will be used in an automatic way at the telescope to guide in scheduling OBs for execution.  The LST range that one specifies for a given OB represents the whole time period within which the OB must fit in order to be scheduled.  This has two consequences:

  • The LST range specified must be at least as long as the execution time of the OB (such that the OB "fits" into the specified window), but should not exceed the execution time by more than 10 minutes.
  • In order to capitalize on the maximum rotation achieved when the target transits the meridian the LST range specified in the OB should be (roughly) symmetric with respect to that LST and sufficiently short that it would not be possible to have the OB fully executed on either side of culmination, but not so short that it compromises the chances that it can be scheduled at the telescope.

If in doubt, contact the User Support Department by clicking on "Ask for help" within the ESO User Portal, or by sending an e-mail to

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