Use Case:  Do one image analysis with a star

Description:  Process defocus signal to be delivered by STRAP via astigmatism measurement. Used for correcting M2.

Role(s)/Actor(s): 
Primary:VLTICS-ISS
Secondary:FSS-STRAP

Priority: Desirable

Performance: some seconds

Frequency: any time

Package Assignment:  Active Optics.

Preconditions: 

• ...

Basic Course: 

• ...
  Alternate Course: ...
  Exception Course: ...
  Postcondition: ...
  
• ...
  Alternate Course: ...
  Exception Course: ...
  Postcondition: ...
  

Subflow: 

• Do first step
  Alternate Course: Optional Alternate Course Title1.
  Exception Course: Optional Exception Course Title 1.
  Postcondition: Optional step postcondition description
• Do second step

Alternate Course: 

• ...
  Exception Course: ...
  Postcondition: ...
  
• ...
  Exception Course: ...
  Postcondition: ...
  

Exception Course: 

• ...
  Postcondition: ...
  Optional step postcondition description
• ...

  Postcondition: ...
  Mandatory postconditions that validate the exception course.

Postconditions: 

• ...
• ...

Issues to be Determined or Resolved:  How the focus signal is elaborated remains to be defined: inside STRAP firmware or outside STRAP using diagnostic on Mean Value of APD Counts. The second solution is probably the most appropriate since we need anyway to average over typically >30 sec as for Active Optics to averaged out atmospheric contribution.

Notes:...

Last modified: Thu Jun 28 12:57:27 UTC 2001