The OB components

​

The detailed OB structure depends on the instrument you need to use, as each instrument offers a variety of observing modes and has different limitations. However, 3 main components can be identified:

​

• the templates

• the finding chart

• the readme

​

Each of these provides a different set of information necessary to execute your observation. We provide here a description of each component together with a tutorial explaining how to create and prepare it in p2.

​

​

The templates

​

All ESO instruments in all observing mode need to go through few steps to complete an observation. These steps are codified into templates. A template is nothing else that a series of fields that need to be filled in with necessary information, e.g. the target coordinates, the exposure time of your observation or a possible dither pattern. 

The ESO instruments need to acquire the target before the observation. This is done through a short-exposure image, the acquisition, at the target coordinates, to check where the target is and to assure that we are observing what you want (e.g. the target in the slit for spectroscopy). To this purpose, you need to fill in an acquisition template. Below you can see an example of an acquisition template in p2, the tool for the OB preparation, for an imaging polarimetry observation with FORS2 at UT1.

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

In this example, the template requires to set the exposure time for the short acquisition to identify the target, the FORS2 CCD preference, if any, the Position Angle (PA), information on the Guide Star, which is not mandatory and is left to the default values in the example, the FORS2 collimator and filter you would like to use for this short acquisition.

Different instruments and observing modes differ in several fields, but the purpose of this template is the same for all.

​

Once the acquisition template is filled, you are required to choose the science template of your observation. In particular cases and depending on the complexity of your observation, this might require more than one template. Below, you see an example of a science template in p2 for the same acquisition template shown above.

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

It is not important to dwell here on the details of the entries of this particular template. The purpose of the example is to show you that each science template is organize to let you give us all the possible details to obtain the observation you need. The help you doing that in an efficient, we provide for each instrument non only a detailed User Manual but also a Template Manual, that explain template by template all the necessary entries. For each instrument you can find all the relevant link in the Instrument table.

​

​

What is a finding chart.

A finding chart is one or more images associated to an OB to show the where the target is in the instrument FoV and possible where are reference or guide stars. It is particularly useful to the astronomer at the telescope to understand the nature of your target and to have some clarification in case of doubts. The finding chart together with the acquisition will assure that we are observing what you really want us to observe for you.

In general, a finding chart has to be attached to each OB. Exceptions are possible for some instruments, in which case this is specified in the instrument-specific rules, which can be found by selecting the instrument from the pull-down instrument selector menu in the upper right of this web page.

​

General Finding Chart Requirements

Regardless of the instrument, finding charts must have all the following characteristics:

• Clearly indicate the Observing Run ID.

• Clearly indicate the PI Name.

• Clearly indicate the OB Name or Target Name, as used in the OB to which it is attached.

• The target(s) position(s) must be clearly indicated.

• The entire instrument field-of-view must be shown.

• North and East must be clearly indicated.

• The scale must be indicated by drawing a bar and writing the bar length in arcseconds or arcminutes.

• The wavelength range of the image must be indicated. Whenever possible, finding charts should have similar central wavelength to observations (e.g. DSS charts are often inappropriate for IR observations, e.g. near the galactic equator).

• The images should be negative, i.e. dark objects on light background.

• The output files must be in JPEG format and their size must be less than 1 Mbyte.

• Positions of spectroscopic acquisition reference stars, if any, should be marked.

• Spectroscopic finding charts must indicate the slit(s) position(s) clearly (unless slits are aligned along the parallactic angle)

 

To let us properly identify your target, the finding charts must have sufficient quality and resolution. For most instruments, the finding chart can be easily created at the required resolution in the tool p2. Please read the P2 finding chart tutorial for a detailed description on how to attach finding charts to OBs.

 

The Readmy file

​

The README file is a list of instruction for the astronomer at the telescope. It must be informative but concise. It should contains an overview of the observation, of the aspects specific to it, and an instrument-dependent checklist. Here you should tell us if there is anything we should be pay attention to.  As templates and finding chart, the the README file can be filled in the p2. 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 (this is the approval for breaking an OB or container rule), 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 in p2.

• 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 confirm that you have taken all these aspects into account.

​