Use Case: Calculate calibrated M2 position and set M2

Description:  Apply open-loop (or "look-up") correction of M2 focus/centering according to altitude angle. Focusing and centering is done usig calibration data, i.e. focus and centering from lookup table, corrected for actual temperature and altitude positions.

Role(s)/Actor(s): 
Primary:Operator, Maintenance,VLTICS-ISS
Secondary:M2

Priority: Major

Performance: Some seconds

Frequency: any time

Package Assignment:  Active Optics.

Preconditions: 

• M2 Online

Basic Course: 

• Send command ONECAL
  Alternate Course: Differential settings
  
  • ATCS gets zenith angle of last setting
• ATCS calculates absolute or differential positions and save them to database
• ATCS sends command Do one Correction
  
• ATCS saves zenith angle of last setting
• ATCS returns OK reply

Issues to be Determined or Resolved: 

Notes: M2 centering should not be needed if the Telescope structure meets its specifications based on "no M2 active correction allowed to compensate gravity deflection". This "look-up" correction Use Case for the AT, so that it is readily available, should gravity deflection appear a problem during testing in Europe.

Last modified: Mon Feb 25 10:25:10 UTC 2002