Frequently Asked Questions

Observation Preparation

  • Do I need to account for overheads in my total exposure time when submitting Service Mode OBs?

    Answer: Yes. The Observing Programmes Committee (OPC) allocates total time = integration time + all standard operational overheads. To estimate your operational overheads, see the individual instrument User's Manuals and/or use the Execution Time Report function in the P2PP tool.
  • How many special calibration OBs do I have to submit?

    Answer: You should assume that your science OBs will be executed completely independently of each other, possibly on different nights, and take into account that no calibration OB will be executed more than once. You should submit enough special calibration OBs to cover that situation. Example: if you need to observe and flux-calibrate six targets in a filter that is not supported in the calibration plan of the instrument, you need to provide six special calibration OBs to allow for the case in which each target is observed on a different night. This must be done so even if the same calibration star can be used for all the science targets. For assistance, contact the User Support Department (
  • I already installed P2PP on my computer when I prepared Phase 2 material for a previous Period. Do I need to install the latest version to prepare my OBs for the current Period, or will the version I have work?

    Answer: So long as your observing run is for a La Silla instrument and the version that you used in the past was version 2.13.1 you do not need to re-install P2PP. If you have used an earlier version you must download and install version 2.13.1 for La Silla observing run.  If your observing run is for Paranal (VLT, VLTI, VST or VISTA) then please download the latest version of P2PP3.
  • Can I specify different observing constraints(e.g. seeing, transparency) at Phase 2 than I specified in my Phase 1observing proposal?

    Answer: You can relax your constraints to increase the chances of execution of your OBs (for example, if you specified Seeing = 1.0 or better at Phase 1, you can specify Seeing = 1.2 or better at Phase 2). However, more stringent constraints (like Seeing = 0.8 at Phase 2 in the previous example) are not allowed, as an essential ingredient of the long-term scheduling of Service Mode programmes over the semester is the constraints that users of approved programmes specified at Phase 1.Allowing more stringent constraints at Phase 2 would thus endanger the completion of even the highest ranked programmes. An allowed exception to this are OBs needed to flux-calibrate observations that can be mostly done under non-photometric conditions, provided that accurate flux calibration is needed for the scientific goals of the programme and that the execution time under photometric conditions does not exceed 20% of the allocated time.The values in the OB constraint sets that are selected (and approved)during Phase 2 preparation (and review) cannot be changed later during the observing period.This is explained in more detail in the Phase 2 Service Mode Guidelines web pages.
  • I received the notification of time allocation, but when starting P2PP my new program does not appear among the folders

    Answer: Unless you have rebuilt your P2PP installation from scratch, the list of your scheduled runs is not updated every time you start P2PP (note that this applies also if you installed a new version of P2PP but kept the existing local cache; see the P2PP User Manual for details). Thus, when you need to work on new runs using an existing P2PP installation, you need to click on the Download/refresh Observing Runs option under the File menu in P2PP. This will create a folder for each newly approved observing run.
  • How do I get my P2PP ID and password?

    Answer: The P2PP ID and password correspond to the ESO User Portal username and password of the Principal Investigator (PI), or of the Phase 2 Delegate (in case the PI has delegated Phase 2 access to another User Portal registrant).  If you as PI of a scheduled run, or as a Phase 2 Delegate, have forgotten your User Portal username and/or password please use the appropriate corresponding link(s) on the User Portal login page.

    If you have no accepted programs as PI but wish to learn the use of P2PP, you can use the tutorial account (ID '52052', password 'tutorial') set up for this purpose.

  • After reviewing my Phase 1 proposal, I have realized that I can observe a better set of targets than the ones I listed then. Since the scientific goal is the same, can I simply change the list of targets?

    Answer: In principle, no. The reason is that the allocation of time in Service Mode is a complex process in which one of the main ingredients is the pressure factor on each right ascension interval, derived from the distribution in the sky of the targets that the accepted programmes proposed at Phase 1. The Long Term Schedule that results from the time allocation process would thus be invalidated if changes of target were allowed at Phase 2, this is, after the time allocation has been made.

    It is however possible to accept a limited number of target change requests in cases for which a sound scientific justification exists, such as the existence of new observations that demonstrate that a given object of the original sample had been misclassified and is not relevant to the purpose of the programme any more. Target change requests are reviewed by ESO to ensure the strength of the justification and also that there is no other approved programme that intends to execute observations of the new target in a similar configuration.

    Target change requests must be addressed to the ESO User Support Department via a dedicated Target/Instrument Setup Change web form.

  • How can I check-out my OBs to modify them ?

    Answer: Use Check-out... in the P2PP main window File menu. This will give you access to the ESO Database Browser, where you can use different selection criteria to display your OBs. Once you have highlighted the relevant OBs, you can check them out by choosing theCheck out option in the ESO Database Browser Filemenu. A more detailed description of this procedure can be found in the webpage dedicated to the OB Resubmission Procedures. For users of the new P2PP version 3 tool there is a video tutorial explaining how to check-out individual OBs and OBs within containers. It is important to notice that when OBs are within containers, both check-in and check-out have to be done for the container (i.e. select the container, not its children OBs).
  • How do I prepare my Phase 2 proposal for APEX?

    Answer: APEX does not use P2PP, but a web-based form . The APEX Phase 2 deadline is the same as the P2PP deadline. Should you have questions about your Phase 2 preparation you can contact the ESO APEX Project Scientist Carlos De Breuck .
  • I have an accepted proposal which consists of a pre-imaging run and a follow-up multi-object spectroscopic (MOS) run. May I submit only the pre-imaging OBs now, by the Phase 2 deadline, and the spectroscopic OBs later?

    Answer: Yes, you should submit only the pre-imaging OBs (i.e. no dummy MOS OBs should be submitted at the general Phase 2 deadline). ESO will make every possible effort to execute all pre-imaging as early as possible, and will release pre-images immediately. In effect all pre-imaging OBs will be treated as ``carry-under OBs'', meaning that they will be executed as soon as they are ready, even if that is before the period starts. For the Phase 2 proposers this means that it is important to submit pre-imaging OBs as soon as possible, even long before the deadline. The earlier valid OBs are submitted, the earlier the pre-images will be taken, and the higher the probability that follow-up MOS observations will be completed within the narrow window of opportunity.
  • Can I directly interact with my contact scientist,rather than sending mail to

    Answer: We discourage you from doing it. User support astronomers have other professional commitments that sometimes cause them to be away and have limited access to email and, especially, to the tools used in ESO operations, which may cause delays in addressing problems. If you send your request to we will ensure that it is always given prompt attention by an expert on the instrument that your run uses, even in periods when your contact scientist cannot deal with it.
  • I submitted a Waiver Request and it was granted, but I still get the same errors related to the request when I verify my OBs in P2PP. What is wrong?

    Answer: The short answer is nothing, this is normal. The reason is that the error condition that was waived as a result of your request being approved will be ignored by the receiving application in Garching when you check in your OBs. There is no mechanism available to "tell" your P2PP application to similarly ignore the error.
  • What is the accuracy of the UTs pointing and tracking?

    Answer: The UTs have a pointing accuracy of 3 arcsec RMS. The expected tracking accuracy under nominal wind load is 0.1 arcsec RMS over 30 minutes when field stabilization is active. The UTs also have the capability of tracking targets with additional velocities (e.g. Solar System targets) under full active optics control. Proposers who need this capability should specify the additional velocities in RA and Dec for their targets. Please check here for further details on UTs performances


Data Distribution

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