Configuring a field of fibres for a 2dF observation is a complex procedure. The configure software allows astronomers to prepare input files for the fibre positioner. It reads an ASCII formatted catalogue and allows astronomers to automatically or manually allocate fibres to targets using a graphical user interface. Binary files can be saved which can then be directly loaded into the 2dF system.
- Current Version
- Creating an input file
- Running Configure
- Guide to complex configurations
- Guide to locking a sub-set of allocations
- Guide to Nod and Shuffle observations
- Guide to temporarily disabling fibres
- Frequently Made Mistakes
The current version of configure is 7.17 (released November 29, 2012); it is a version for AAOmega, HERMES, 2dF, 6dF, and Ozpoz and may be downloaded from the ftp site.The current version of Configure implements a Simulated Annealing (SA) algorithm. The advantages of SA are explored thoroughly in Miszalski, Shortridge and Saunders et al. (MNRAS, 2006, 371, 1537); arXiv:astro-ph/0607125), and are summarized in an article in the February 2006 AAO Newsletter. In short, SA provides:
- Increased yields for complex fields
- Optimal target priority weighting
- Highly uniform and quantified sampling behaviour
- High completeness for fibre pairs when allocating a field for Cross Beam-Switching observations
For users who do not wish to use Simulated Annealing, a version of Configure which uses the original "Oxford" algorithm is also packaged with Configure7.3 and later packages.
There are currently versions available for Linux (RH3E) and Mac-OS. Note, the Mac version is code named Darwin by the Operating system. This should run on most modern flavors of the hardware.
The older Configure7, is still available for Solaris, Linux and Darwin.
All you have to do is tar and unzip the appropriate gzipped (.tar.gz) file. e.g. for the Linux (32 or 64 bit) version:
tar -zxvf configure-7.#.Linux-Intel64bit.tar.gz
Then you just have to run the Configure executable:To run Configure, first set the environment variable:
> setenv CONFIG_FILES /path/configure-7.#.Linux/data_files/
Download the relevant astrometry files (see below) to this CONFIG_FILES directory. Then
configure-7.#/Linux/configure --- For the (default) Simulated Annealing code
configure-7.#/Linux/configureTrad --- For the original "Oxford" algorithm
For the Mac Lion or Snow Leopard versions move the untarred and unzipped directory to /Applications/ and Configure can be started by double-clicking Configure in its directory.
To run configure, you will also need files giving the 2dF astrometry model: tdFlinear0.sds, tdFlinear1.sds which are the linear astrometric coefficients for plate 0 and plate 1, respectively; tdFdistortion0.sds, tdFdistortion1.sds are the distortion maps for plate 0 and plate 1, respectively. You will also need the current fibre information (availability and park positions for all fibres [1-400]): tdFconstants400.sds. Unless you are configuring at the AAT, you should get the most recent version of these files. They can be fetched by anonymous ftp from the AAO from ftp://site-ftp.aao.gov.au/pub/local/2df/latest_config_files. Please configure your fields with the latest astrometric and fibre information.
NOTE: Even if you do use the most current fibre and astrometric information, you will still have to tweak your fields at the telescope, since things can and do change on very short notice. This is especially true at the start of your run.
Creating the input files for Configure is a crucial part of preparing for successful AAOmega observations. The necessary steps are described in the Guide to creating a Configure Input File.
There are a number of options available within the Configure program. These are described in the Guide to Running Configure.
How to set-up observations with target densities > 800 targets per 2 degree field is described in the guide to making Complex Configurations.
How to force the repeat observation of a sub-set of high priority targets, while including new targets, is described in the guide to locking allocations.
How to prepare for and carry out Nod and Shuffle observations is described in the guide to setting up Nod and Shuffle observations.
A method for temporarily deactivating specific fibres for the 2dF positioner (necessary for Nod and Shuffle Observations) is described in the guide to the set_fibre_state tool.
For a very densely populated field, the time taken to generate the collision matrix is a stronger function of N than NxN. In this regime, simply reducing the number of targets in the input file will not necessarily increase the speed of the collision matrix generation significantly. In this case one should sparse sample the very dense regions of the field. The total number of targets in the input file can remain quite large, provided the numbers of targets within the high density regions is small. Since the minimum fibre separation is of the order of 30 arcseconds, there is little to be gained, even with SAconfigure, in having a high target degeneracy on scales smaller than 0.5-1arcminuates.
Do not allow multiple instances of a target to appear in any given .fld file.
Check the selected fiducial stars. Unless you have selected the Weight Peripheral Fiducials option, Configure can pick some rather poor guide star selections (e.g. all stars in the centre). Do check to make sure the arrangement is sensible (i.e. well separated across the field plate)
Check the number of sky fibres allocated. Unless you have selected the Enforce Sky Quota option Configure can sometimes leave very few sky fibres, if any. This might invalidate your whole observation as it is difficult to undertake sky subtraction without these, and so it is important that the number of sky fibres is sufficient.
A large proportion of the issues listed in the general Frequently Made Mistakes are associated with configuration so it is also recommended to read those.
Sarah Brough (firstname.lastname@example.org)