ARO 12 Meter User Manual

Preface

Our intent with this manual is to provide a general reference book for the operation of the 12m millimeter-wave telescope. We have included basic material required for first-time use of the telescope, as well as more detailed information of possible interest to all observers. In addition to this manual, we recommend that first-time users read the companion document Visitor's Guide to the ARO 12m Telescope before coming to the telescope.

We are sure that there is room for improvement in this manual, and ask users to bring to our attention any errors, omissions, or unclear passages. Please note that we actively maintain this manual only as a web page.

There are a number of companion documents which you should consult for more detailed information regarding On-The-Fly observing, the current equipment and calibration status. The following list itemizes these supplementary documents, most of which are accessible via the ARO Home Page.

• The ARO 12m Telescope Equipment and Calibration Status.
• On The Fly Observing at the 12m Telescope.
• On The Fly data acquisition and analysis.
• Visitors' Guide to the ARO 12m Telescope.

PDF versions of this manual can be found here.

Contents

• 1 Introduction
  • 1.1 The Observatory
  • 1.2 Observing Proposals
    • 1.2.1 Proposal Preparation
    • 1.2.2 Proposal Submission and Refereeing
    • 1.2.3 Proposal and Observing Propriety
  • 1.3 Observatory Policy
    • 1.3.1 Staff Responsibilities
    • 1.3.2 Observer's Responsibilities
    • 1.3.3 Maintenance and Repairs
    • 1.3.4 Sharing Telescope Facilities with Other Observing Teams
    • 1.3.5 Observations Under Poor Weather Conditions
      • 1.3.5.1 High Winds
      • 1.3.5.2 Moisture Accumulation In or On the Dome
      • 1.3.5.3 Sun on the Dish
      • 1.3.5.4 Observations Using Emergency Power Generators
      • 1.3.5.5 Safety Rules

• 2 Getting Started
  • 2.1 What to Bring to the Telescope
  • 2.2 Startup Checklist
  • 2.3 Basic Data Reduction with UniPOPS
  • 2.4 Alternate Data Analysis Packages
    • 2.4.1 CLASS
  • 2.5 Data Archiving and Export

• 3 Instrumentation
  • 3.1 Telescope Site Layout
  • 3.2 Telescope Optics
  • 3.3 Receivers
  • 3.4 The Local Oscillator System
  • 3.5 The IF Section
  • 3.6 Spectrometers
    • 3.6.1 Filter Banks
    • 3.6.2 Millimeter Autocorrelator (MAC)
    • 3.6.3 Continuum Backend
  • 3.7 Computer Equipment

• 4 Tracking, Pointing, and Focus 31
  • 4.1 Tracking Capabilities
    • 4.1.1 Ephemeris Objects
  • 4.2 Tracking Limits
    • 4.2.1 Elevation Limits
    • 4.2.2 Azimuth Limits
  • 4.3 Tracking Error Tolerance
  • 4.4 Sequence of Position Computation Operations
  • 4.5 Subreflector Beam Throw
  • 4.6 Pointing
    • 4.6.1 Continuum and Spectral Line Five-Points
      • 4.6.1.1 Continuum Five-Point Analysis
      • 4.6.1.2 Spectral Line Five-Point Analysis
    • 4.6.2 Pointing Model Equations
    • 4.6.3 Pointing Data Analysis Program
  • 4.7 Focus
    • 4.7.1 Axial Focus
    • 4.7.2 Determining the Axial Focus
    • 4.7.3 Lateral Focus

• 5 Spectral Line Observing
  • 5.1 Startup Checklist
  • 5.2 Sideband Choice
  • 5.3 Spectrometers
    • 5.3.1 Filter Banks
      • 5.3.1.1 The Parallel/Series Option
      • 5.3.1.2 Bad Channel Elimination
      • 5.3.1.3 Frequency Offsets
    • 5.3.2 Millimeter Autocorrelator
      • 5.3.2.1 The 4IF Observing Mode
  • 5.4 Observing Modes
    • 5.4.1 Total Power ONs and OFFs
    • 5.4.2 Position Switching
    • 5.4.3 Absolute Position Switching
    • 5.5.4 Frequency Switching
    • 5.4.5 Beam Switching
    • 5.4.6 Mapping
      • 5.4.6.1 Manual Offsets
      • 5.4.6.2 Grid Mapping
      • 5.4.6.3 When Should I OTF Instead of Grid Map?
      • 5.4.6.4 An Important Note About Spatial Sampling
  • 5.5 Spectral Line Sensitivities
    • 5.6 Calibration
      • 5.6.1 Vane Calibration
      • 5.6.2 Direct Calibration
  • 5.7 Signal Processing
    • 5.7.1 Position and Frequency Switched Data
      • 5.7.1.1 Vane/Chopper Calibrates
      • 5.7.1.2 No-Cal Signal Processing
    • 5.7.2 Beam Switched Data
  • 5.8 Changing the Intermediate Frequency
  • 5.9 Spectral Line Status Monitor

• 6 Continuum Observing
  • 6.1 Startup Checklist
  • 6.2 Selecting an Observing Frequency
  • 6.3 Observing Basics
    • 6.3.1 Switching Modes
    • 6.3.2 Checking the Subreflector Throw
    • 6.3.3 Continuum Sensitivity
    • 6.3.4 The Digital Backend
    • 6.3.5 Software Signal Processing of Digital Backend Data
  • 6.4 Observing Procedures
    • 6.4.1 Point Source ON/OFF Observing Procedures
      • 6.4.1.1 The ON/OFF Sequence
    • 6.4.2 Mapping Extended Sources
      • 6.4.2.1 Grid Mapping
      • 6.4.2.2 Continuum On-The-Fly Mapping
  • 6.5 Utility Observing Routines
    • 6.5.1 Sky Tip Procedures
      • 6.5.1.1 The SPTIP Analysis Procedure
      • 6.5.1.2 The STIP Reduction Procedure
  • 6.6 Calibration
    • 6.6.1 Vane Calibration
    • 6.6.2 Hot/Cold-Load Calibration
    • 6.6.3 Calibration of the Flux Density Scale
  • 6.7 Continuum Status Monitor

• Appendix A Pointing Equations for the 12m Telescope
  • A.1 Primary Pointing Equations
    • A.1.1 Secondary Pointing Corrections

• Appendix B The Relationship Between Flux and Brightness Temperature
  • B.1 Uniform Disk Source
  • B.2 Elliptical Gaussian Source

• Appendix C Temperature Scales and Telescope Efficiencies
  • C.1 Definitions
  • C.2 Relations Between Temperature Scales
  • C.3 Telescope Efficiency Measurements
    • C.3.1 Corrected Main Beam Efficiency
    • C.3.2 Main Beam Efficiency

• Appendix D Spectral Resolution and Sensitivity Bandwidth in Spectrometers
  • D.1 Function Integrals
    • D.1.1 Sinc
    • D.1.2 Gaussian
    • D.1.3 Hanning
    • D.1.4 Hamming

• Appendix E Walsh Function Modulation

• Appendix F The Radiometer Equation for Position Switched Measurements

• Appendix G The 12m Telescope Primary Focus Plate Scale