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Procedure: SHANEAO Sodium Filter

When deploying the Sodium filter into the light path, set cx=-0.03 and cy=-0.03 in the fieldsteer.tcl GUI to correct centering.

When retracting the Sodium filter from the light path, remember to go Back On-Axis in the fieldsteer.tcl GUI.

The need to modify cx and cy possibly results from tilt during installation.
The (narrower passband) Sodium filter from the original Lick AO system was installed into ShaneAO 2017-01-14.

Manipulation Using Keywords

The Sodium filter stage is controlled by the keyword SODIUMFILT, with values In, Out and Moving/Unknown.
 
   gshow -s saomot sodiumfilt 
   SODIUMFILT = In 
    
   modify -s saomot sodiumfilt=out 
   setting sodiumfilt = Out (wait) 
    
   gshow -s saomot sodiumfilt 
   SODIUMFILT = Out 
   
A 'modify' of SODIUMFILT will not return until the filter flipper has changed position (or times out after 5 seconds of waiting).

SODIUMFILT is built upon two lower-level keywords:

  • SODIUM_CMD controls the output signal to the filter flipper:

    modify -s saomot SODIUM_CMD=In

  • SODIUM_POSN monitors the input signal from the filter flipper:

    gshow -s saomot SODIUM_POSN

    SODIUM_POSN = In

(SODIUMFILT is set to Moving/Unknown when SODIUM_POSN does not match SODIUM_CMD)

Change Log:

2017-01-14: Updated.
2014-12-01: First version.

This document last updated (UTC): Tuesday 04 March 2025