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AAOmega: set_fibre_state tool


From time to time, it can be desirable to temporarily deactivate specific fibres for the 2dF positioner. The most common reason for this is to set up a field for Nod and Shuffle observations where a number of fibres need to be disabled in addition to those that are un-available due to damage. The temporary removal of fibres with poor characteristics (e.g. fringing fibres is also possible.

To facilitate the temporary disabling of fibres a utility program has been packaged with Configure from v7.7 onwards.

The routine set_fibre_state can be found in the base directory of the Configure distribution. The utility should be set to be locally executable. Running the script will then provide an introduction to its usage. Under LINUX this looks like:

LINUX> chmod +x set_fibre_state
LINUX> ./set_fibre_state
Insufficient arguments.
2dF set fibre state program - Usage:
./set_fibre_state <tdFconstants400.sds> shuf 0|1|both
./set_fibre_state <tdFconstants400.sds> file 0|1 <file>
./set_fibre_state <tdFconstants400.sds> file both <file1> [<file2>]
./set_fibre_state <tdFconstants400.sds> restore <file>

In the syntax above the arguments in <> are user supplied input files.

There are three basic modes of operation, shuffle, file (with two syntax options) and restore. Shuffle will create a new file for tdFconstants400.sds file with the fibres on one or both plates correctly disabled for nod-and-shuffle observing whereas the file option allows the user to selectively disable fibres.

In all cases, the script should be run on the tdFconstants400.sds file found in the /path/configure-V.V/data_files/ directory. Doing this away from the telescope requires installing the latest tdFconstants400.sds file. The current tdFconstants400.sds file can be found through the main Configure page. The code will create a back up of the old constants file, tdFconstants400.sds.bck, and a restore file tdFconstants_changes.txt which can be used with the restore option to reverse the changes made to the tdFconstants400.sds file.

Note for configure-7.9-1 onwards: The mapping of fibres in 2dF is not always 1-to-1 with the fibre slit position. From v7.9.1 onwards, set_fibre_state requires access to the spec_fibres.txt file, which is available from the support astronomer, in order to achieve this mapping. The fibre ordering is currently a 1-to-1 mapping.

Nod and Shuffle mode


This mode creates a tdFconstants400.sds file with every alternate AAOmega fibre (at the AAOmega slit end NOT at the positioner end) disabled so as to be masked off during Nod and Shuffle observations. By default, the script disables even numbered fibres, since the 8 AAOmega guide fibres are even numbers (50, 100, ... 350, 400) and are already disabled on the CCD (by virtue of not being in the slit unit). They are left active so as to be positionable by 2dF on the field plate.

Run the script with:

./set_fibre_state
tdFconstants400.sds shuf 0|1|both shuf

The 0|1|both option allows the user to make the relevant changes to only one plate or to both plates. For N+S, the both option is typically required.

File mode


The File mode option allows the user to make an ascii file which lists the 2dF positioner pivot number for one or both 2dF field plates, and then disables the listed fibres. The text file format is a simple list of integers, one integer per line, with lines beginning with # considered comments and hence ignored. An individual field plate can be modified with:

./set_fibre_state tdFconstants400.sds file 0 text.file0

or

./set_fibre_state tdFconstants400.sds file 1 text.file1

Or both plates can be modified at once using the format:

./set_fibre_state tdFconstants400.sds file both text.file0 text.file1

Restore mode


The restore option uses the tdFconstants_changes.txt created by the set_fibre_state to reverse the changes to the setup file. The syntax follows:

./set_fibre_state tdFconstants400.sds restore tdFconstants_changes.txt

Note, this will reverse the last set of changes made to the tdFconstants400.sds file. If multiple changes have been made, while experimenting with the script, it is probably safer to simply overwrite the tdFconstants400.sds with a private back up (note, multiple changes to the file may mean that the task's own backup file, tdFconstants400.sds.bck, is not actually what the user wants. A private back up is invaluable here).

Sarah Brough (sb@aao.gov.au)