1. PRIMA Astrometry Calibration and Operation Plan PRIMA Astrometry Calibration and Operation Plan VLT-PLA-AOS-15759-0001 - draft Scope of the Document  This document shall provide the consortiums suggestions as input and support for the official PRIMA Astrometric Operations and Calibration Plan which falls under the responsibility of the ESO PRIMA instrument scientist.  It gives an overview of the PRIMA Astrometric Operation principles and modes and the calibration requirements derived in the Astrometric Operations and calibration strategy (VLT-TRE-AOS-175754-001). It describes in a hierarchical view the long-term Astrometric Operations and Calibration Plan for PRIMA as well as the specific Operations and Calibration Plans for special alignments and calibrations and standard and non-standard astrometric science observations.  At this draft stage, only a preliminary Table of Contents (to outline the structure of the document) with keywords and suggestions about the contents going into the chapters is outlined, but no real specific content yet.

2. PRIMA Astrometry Calibration and Operation Plan PRIMA Astrometry Calibration and Operation Plan VLT-PLA-AOS-15759-0001 - draft Table of Contents CHAPTER 1: INTRODUCTION 1.0Scope of the document 1.1Acronyms CHAPTER 2: PRINCIPLE OF PRIMA ASTROMETRIC OPERATION CHAPTER 3: PRIMA ASTROMETRIC CALIBRATION REQUIREMENTS 3.1General PRIMA alignment and subsystem calibration 3.2Standard astrometric calibrations 3.3Target and goal specific calibrations 3.4Long-term stability and consistency checks CHAPTER 4: LONG-TERM ASTROMETRIC OPERATIONS AND CALIBRATION PLAN CHAPTER 5: SPECIFIC ASTROMETRIC OPERATIONS AND CALIBRATION PLANS 5.1Initial calibrations after reconfiguration 5.2Standard daily Operations and Calibration Plan 5.3Operation Plans for special calibrations and regular long-term consistency checks 5.4Modified Operations and Calibration Plans

3. PRIMA Astrometry Calibration and Operation Plan PRIMA Astrometry Calibration and Operation Plan VLT-PLA-AOS-15759-0001 - draft Chapter 2: Principle of PRIMA Astrometric Operation Short description of PRIMA subsystems Overwiev of PRIMA operating modes: [1] Fringe tracking [2] Imaging mode [3] Differential astrometry Operation principle of PRIMA astrometric mode

4. PRIMA Astrometry Calibration and Operation Plan PRIMA Astrometry Calibration and Operation Plan VLT-PLA-AOS-15759-0001 - draft Chapter 3: PRIMA Astrometric Calibration Requirements 3.1 General PRIMA alignment and subsystem calibration Overview, Summary of Operation and Calibration Strategy (VLT-PLA-AOS-15751-001) 3.2 Standard astrometric calibrations Overview. Zero OPD, … 3.3 Target and goal specific calibrations E.g., hour angle / elevation dependencies, color difference target and reference star, Trade-offs between science goals, anticipated astrometric accuracy, and time & effort spent for special calibrations, … 3.4 Long-term stability and consistency checks E.g., time scales and conditions for regular observations of standard calibrators

5. PRIMA Astrometry Calibration and Operation Plan PRIMA Astrometry Calibration and Operation Plan VLT-PLA-AOS-15759-0001 - draft Chapter 4: Long-term Astrometric Operations and Calibration Plan  General outline of long-term PRIMA astrometric operation and calibration plan. Hierarchical view, to put things in an order, no detailed plans (these are in Chapter 5): 1.Define at what intervals which special calibrations and consistency checks should be repeated 2.Initial calibrations and alignments after reconfigurations (e.g., baseline change, reconfiguration of a subsystem, etc.) 3.General Operations and Calibration Plan for an observing run, i.e, a number of consecutive nights with one coherent observing plan 4.Daily standard Operations and Calibration Plan

6. PRIMA Astrometry Calibration and Operation Plan PRIMA Astrometry Calibration and Operation Plan VLT-PLA-AOS-15759-0001 - draft Chapter 5: Specific Astrometric Operations and Calibration Plans Flow charts, block diagrams, and explanations 5.1 Initial calibrations after reconfiguration Special operation and calibration plans for initial alignments and subsystem calibrations 5.2 Standard daily Operations and Calibration Plan Flow chart like, e.g., Fig. 5-3 in VLT-SPE-ESO-15700-2207 5.3 Operation Plans for special calibrations and regular long-term consistency checks For special observation / calibration blocks that differ from standard astrometric science operations (e.g. baseline calibration, special standards, etc, if different than standard astrometric observations) 5.4 Modified Operations and Calibration Plans Like standard daily operations and calibration plan, but including special calibrations for “non-standard” astrometric observations with special calibration needs, reduced accuracy requirements, etc.

7. Pointing the telescope Acquire PS, SS, and AO-RS Close PS fringe tracking loop on FSU-B with main DL Closing AO loop Zeroing / reading metrology Feed PS into both A and B feeds with STS Detect fringes on FSU-A by scanning DDL around zero ref Feed SS into feed A with STS Move DDL to anticipated differential delay Detect / measure fringes on FSU-A Read metrology Track fringes with DDL Integrate n × 1min Check ZP and reapeat 30min Swap PS and SS feeds and repeat