AAO Subaru
Echidna

Spine-to-Object Allocation Software
User Manual

  1. Table of Contents

  2. Introduction

    This manual describes how to use the spine-to-object allocation software to allocate fields for use with the FMOS-Echidna fibre-positioning instrument on the Subaru Telescope.
  3. Overview

    The spine-to-object allocation software is responsible for determining the allocation of target objects to individual spines for each observation made using the FMOS-Echidna instrument. It ensures that the final allocation of objects is near-optimal according to a set of specified parameters. (discussed later)

    This software is executed offline, typically by the Astronomer requesting an FMOS-Echidna observation. It accepts as input a list of target objects with associated mean RA/Dec coordinates, priority, magnitude, etc and outputs an allocation file (.s2o) which specifies all of the necessary information required by Echidna to configure itself for the observation. Echidna's control software is able to read the allocation file and configure itself without any additional knowledge of the field.

  4. Basic Operational Procedure

    This section aims to give a primer on how to use Echidna's allocation software. First-time users will find it useful to read this section first and experiment with the example fields (found in the examples directory) before moving on to later sections which describe features in more detail.

    1. Install the software
      If the allocation software is not installed on your system, you will need to follow the installation instructions.
    2. Prepare the source list
      To ensure that no significant flux losses occur as a result of fibre mis-placement, the selected targets should have less than 0.3" relative astrometric error across the FOV. Guide stars should ideally be taken from the same positional catalogue as the astronomical sources to eliminate systematic offset errors. Guide star magnitudes should be R≤16.5 magnitude and proper motion (particularly in the case of relatively bright guide stars or old positional data) should be checked. Ideally the magnitude range of the guide stars should be minimised to avoid saturation issues with Echidna's autoguiding camera.
    3. Create the input file
      The input file format is described below. Be sure to include:
      • 'F' (Guide) targets
        The allocation software will generate a warning if less than 3 guide spines can be allocated.
      • 'K' (Coordinate calibration) targets
        Several of these targets will be imaged by the sky camera during field acquisition to optimise the initial telescope pointing. Each field should have at least 5 coordinate calibration targets (of magnitude R≤15) spread across the field, including one near the field centre.
      • 'P' (Program) targets
        The science objects you wish to acquire spectra for.
    4. Get updated instrument specification file
      The Subaru FMOS-Echidna website should keep an updated version of the echidna.instr file. Hopefully, it is here. This file is used by the allocation software. By using the most-current version, the software will be aware of any broken/deallocated spines and can more optimally allocate fields.
    5. Invoke the allocation GUI
      spineToObject.tcl &
      To prevent the allocation software from accessing the Subaru website to check for an updated spine list, set the $NO_CHECK_SPINE_LIST_UPDATE environment variable to "true". ie.
      export NO_CHECK_SPINE_LIST_UPDATE=true
    6. Start the allocation wizard
      Allocation Operations ⇒ Allocation Wizard (or Ctrl-w)
      You should see a dialog similar to the one below (without the text on the right-hand side).

      Wizard dialog

      Each of the 8 buttons initiates an operation that forms part of the basic allocation procedure. You should step through each operation (top-down) to make a valid allocation.

      • Magnitude filter
        Setup magnitude filtering of science & guide objects.

        Magnitude filter dialog

        Objects with an apparent magnitude value outside the specified magnitude range are disabled but still stored in the .s2o files. Disabled objects are never visible/accessible from the GUI & are never allocated by the allocate program.
        Note: this option can be performed anytime. ie. it will filter the objects of any loaded file.

      • Open file
        Select a .fld or .s2o file to load.

        Open file dialog

        Note: When a .fld file is opened, the allocation program will immediately convert it into an allocation (.s2o) file. The Command Output window should popup and indicate whether or not this conversion was successful. Errors are highlighted in red, warnings are highlighted in blue. If an error occurs you must edit the input file and reopen it to continue. The error messages are quite verbose and should aid in discovering the source of the problem.

      • Field header

        Field header dialog

        Set appropriate values for all fields in the Field Information window. Positioning the mouse over each field will raise a help popup with additional information about the field. Click Apply once you have finished. Further information about each field is here.
        Note: It is important to set these parameters before performing an allocation as they directly affect the allocation algorithm and constraints.

      • Position angle Find a good Position Angle
        This option will automatically calculate the optimal position angle. A good position angle should allow at least 3 guide objects to be allocated. Allocating less than 3 guide objects can lead to sub-optimal autoguiding performance.
        Alternatively, the position angle can be explicitly set/overridden using the POS ANGLE field in the Field Information window.

      • Allocation setup
        Specify some parameters used during the allocation operation.

        Allocation setup dialog

        If the use grid option is selected, allocate will generate a sky target at the "home" position of each spine. Note that any sky (ie. 'S') objects in the input file will be used first (if possible) when allocating sky targets.

        Note: allocate will allocate as many sky-subtraction targets as possible using unallocated spines (unless the minimum is set to zero). If the minimum number of sky-subtraction targets cannot be achieved using unallocated spines, allocate will deallocate low priority science targets and use those spines.

        Note: for Beam-Switching and Cross-Beam-Switching fields, the minimum number of sky-subtraction targets should be set to zero.

      • Allocate
        Automatically allocate objects
        When this operation completes the field plate will be re-rendered to display the allocation state. You can generate statistics pertaining to the allocation by clicking the 'Calculate' button in the Field Information window.

        The allocation software will automatically disable:

        • science targets that are too close together - preferentially disabling the lower priority object
        • non-guide targets that are outside the instrument FOV
        • science targets that cannot be reached by any active spine
        • guide targets that are outside the specified guiding magnitude range
        • science targets that are outside the specified science magnitude range
        • any targets that have a priority of zero
      • Create DSS File
        Create a Digital Sky Survey file of sky targets being utilised so the user can ensure there is no contamination.

      • Save
        Save the output as a .s2o file. You can reload the saved .s2o file and edit it at any time in the future.
  5. GUI Layout

    The Echidna Fibre Positioner Window

    screenshot 1
    Click to enlarge.

    The Echidna Fibre Positioner Window contains a number of sub-windows:

    The Field Information Window

    screenshot 1
    Click to enlarge.

    The Field Information window contains 3 sub-windows:

    The Command Output Window

    Command output dialog

    The Command Output window captures output from the allocate program. The allocate program is responsible for performing most of the complex operations initiated in the GUI. Errors are highlighted in red, warnings are highlighted in blue.

    The Auto-popup on option determine when the command output window should be popped up:

    Every Command Every time the allocate program is invoked.
    Error Detect Only when an error is detected in the output.
    Warning Detect Only when a warning or error is detected in the output. (default)
    Command Fail Only when the allocate program exits with a non-zero return value.
    Never Only pops up the window when explicitly requested by the user.

    The Menus

    Below is a description of each of the menu options found in the allocation software. Note that many of the menu options have associated key bindings which can be a much faster way to perform an operation.
  6. GUI Operations & Features

    Selecting objects

    Items on the field plate can be selected by clicking on them with Mouse-1 or via the View ⇒ Find Object dialog. The Spine Details and Object Details windows to the left of the field plate show information about the currently selected spine and object items.

    Whenever a spine item is selected, the target object to which it is allocated is also selected. If the selected spine is not allocated, the current object selection is cleared.

    To only select an object:

    1. Clear the current selection using View ⇒ Unselect All (or Ctrl-u).
    2. Select the object.

    Allocation operations

    Deallocation operations

    Changing Field Header Information

    Field header dialog

    Note: placing the mouse cursor over any field in a Field Header window will popup a simple balloon help message.

    Zooming & Panning the Field Plate

    The field plate display can be zoomed to a range of different sizes using the View ⇒ Zoom menu and its associated key bindings. You can also specify an area to zoom using Mouse-3-Press ⇒ Drag ⇒ Mouse-3-Release on the field plate.

    Panning around the field plate is accomplished using the scrollbars.

    Allocation Statistics

    Statistics for the current allocation can be generated by clicking the Calculate button in the Field Information window. Statistics are not generated dynamically to reduce display rendering lag.
  7. Command-line Utilities

    Two shell scripts are included with the allocation software. They are:

  8. Input File Format

    .fld input files consist of lines of up to 256 characters. Comment lines are indicated by an * or # as the first character on a line. The header information (describing the field itself, as distinct from the individual targets it contains) must appear at the start of the file.

    Mandatory header fields

    EFLD Must be the first line in the file, & must have the value 1.0.
    LABEL A string describing the target field name.
    UTDATE The UT date of the observation. (yyyy mm dd[.dd])
    CENTRE The field centre in RA/Dec. (hh mm ss.ss ±dd mm ss.s)

    Optional header fields

    EQUINOX Coordinate equinox. Default is J2000.0
    AGMODE Autoguiding mode. Must be one of: "Point-&-Stare", "Beam-Switching" or "Cross-Beam-Switching" Default is Beam-Switching.
    OBS_DURATION Estimated observation duration in seconds. Default is 3600.
    POS_ANGLE Position angle of field plate. Default is 0.
    WAVELENGTH Observation wavelength in nanometres. Default is 1800.
    HA_RANGE The hour angle range that the observation must be valid for. For example, a value of 3 indicates that the observation must be valid from 3 hours before it crosses the local meridian, until 3 hours after.
    NUM_NIGHTS Number of nights (starting from UTDATE) that observation must be valid for.

    Target Object Fields

    NAME Name of object. Cannot contain whitespace or pipe characters - ie. |
    RA Right Ascension (hh mm ss.ss)
    DEC Declination (±dd mm ss.s)
    TYPE Type of object - see Object Types table below.
    PRIORITY Target priority in range 1 .. 9. 1 is the highest priority. Objects with a priority value of 0 are disabled. (ie. stored in the .s2o file but never allocated by the allocate program or visible/accessible from the GUI.
    MAGNITUDE Object apparent magnitude in R. (mm.nn) This field may be set to an asterisk if it is not required - ie. sky targets.
    PROGRAMID Integer value which uniquely identifies a specific project. (Not used) This field may be set to an asterisk if it is not required.
    COMMENT Any remaining text up to the end of the line. (May not contain pipe characters - ie. |)
    Proper-motion values can be specified by embedding a special tag in the comment field of the form:
    (Name=value)
    or
    (Name)=value
    The following names are interpreted by the allocation software:
    PM-RA (value is in arcseconds/year)
    PM-DEC (value is in arcseconds/year)

    Object Types

    F Fiducial (guide) star. This indicates a guide target that can be allocated to a guide spine. (Guide spines are fed to Echidna's autoguiding camera.)
    P Program Object. This indicates a target that can be allocated to any science spine. (Science spines are connected to one of the spectrographs.)
    S Sky target. This indicates a position that can be used for sky-subtraction. These targets are usually allocated to any remaining unallocated science spines.
    K Coordinate calibration star. Several of these targets will be imaged by the sky camera during field acquisition to optimise the initial telescope pointing. Coordinate calibration stars are not allocated to spines.
    C Calibration (or Flux Standard) Star. A special type of sky target that is utilised in sky-subtraction calculations. Calibration stars have a previously well measured spectrum where the absolute flux at each wavelength is known. The difference between its known flux and the observed flux allows the data-reduction software to correct all the spectra for the response function of the instrument, atmosphere etc.
    Z Atmospheric standard star. A special type of sky target that is utilised in sky-subtraction calculations. An atmospheric standard star is a star that is used to calibrate out various absorption features in the Earth's atmosphere. Ideally these are flat featureless stars so that the data-reduction software can correct for absorption. The absolute flux of the star does not need to be known.

    Example Input File

    Here is an example input file in .fld format:
    EFLD 1.0
    # Comments can begin with * or #
    # Generated on Tue Oct 28 10:18:25 2003
    # Mandatory header fields: LABEL, UTDATE & CENTRE
    LABEL A simulated random field.
    UTDATE 2003 10 28.01
    CENTRE 12 34 56.78 -12 34 56.7
    EQUINOX J2000.0
    AGMODE Beam-Switching
    OBS_DURATION 3600
    POS_ANGLE 0
    WAVELENGTH 1800
    
    RandomObject01 12 34 49.23 -12 35 04.4 P 1 15.8 1 Random Object 1
    RandomObject02 12 34 50.03 -12 34 55.2 P 1 17.0 0 Random Object 2
    RandomObject03 12 34 41.02 -12 34 54.5 P 3 17.9 0 PM-RA=-4.24618) (PM-DEC=1.91734) Random Object 3
    
    GuideObject01  12 34 29.43 -12 35 13.4 F 1 16.3 * Random Guide Object 1
    GuideObject02  12 34 36.17 -12 35 53.1 F 1 17.1 * Random Guide Object 2
    
    SkyTarget01    12 34 46.87 -12 34 33.1 S 1 * 1 Sky target 1
    SkyTarget02    12 34 26.77 -12 34 43.6 S 1 * 1 Sky target 2
    		
  9. GUI Options

    Most of the common GUI preferences can be changed via various simple operations. (ie. picking colors using a simple color dialog) However, there are a number of less common options that can only be set in the preferences file. Options that are set in the preferences file take effect when the spineToObject.tcl script is restarted.

    Care should be taken when editing the preferences file as the wrong syntax or an illegal value can result in undefined behaviour.

  10. Software Installation

    System Requirements

    This software should run on any Linux or Mac OS X ≥ 10.4 (PowerPC or Intel) operating system. You will need:

    Installation Procedure

    1. Ensure a Tcl/Tk interpreter is installed on your system. You can download one here for Linux or Mac OS X.
    2. Download the latest version of the FMOS-Echidna allocation software.
    3. Extract the gzip file:
      gzip -dc echAlloc-YYYYMMDD.tar.gz | tar xvf -
    4. Ensure the spineToObject.tcl script is in your $PATH. You will need to edit your ~/.cshrc or ~/.profile file depending on your shell.
    5. Create/update the user preferences file, by starting up the application:
      spineToObject.tcl
      and selecting Options ⇒ Save Preferences.
    6. Edit the preferences file (~/.fmosPrefs) to override options. First-time users will probably only want to check the settings for the main::browserCommand and main::printCommand options.
  11. Reporting a Bug

    Please report all bugs with this software to Dr. Naoyuki Tamura at: naoyuki@subaru.naoj.org.
  12. Acronyms

    FMOS - Fibre Multi Object Spectrograph
    FOV - Field Of View
    GUI - Graphical User Interface
    RA - Right Ascension
  13. This user manual and all associated software are Copyright © 2010 Anglo-Australian Observatory.
  14. Version

    This user manual has the following version information:
    $Id: echidnaUserManual.html,v 1.28 2010/09/26 04:16:37 ss Exp $

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