Mini Explanatory Supplement to the 2MASS 1999 Spring Data Release

I. Introduction

  1. 2MASS Overview
  2. The 2MASS Sky
  3. Top-Level Summary of 2MASS Products
    1. Point Source Catalog
    2. Extended Source Catalog
    3. Image Product
  4. Distribution Mode for 2MASS Products
  5. Data Release Plan
  6. Cautionary Notes
    1. Preliminary Nature of Catalogs
    2. Read2 vs. Read1 vs. Aperture Mags
    3. Persistence
    4. Bright Sources
      1. Read1 Saturation
      2. Fillers
      3. Artifacts and Their Removal
    5. Atlas Images and Atlas Image Holes
    6. Systematic Uncertainties
      1. Global Calibration
      2. Cross-Scan Photometric Bias
    7. High Source Density Regions
    8. Asteroids
    9. Extended Source Caveats
      1. What is an extended source?/multiple stars/E-flag
      2. Excluded Regions Around Bright Stars
      3. Unreliability Due To Meteors
      4. Galaxies
  7. Acknowledgments
  8. Referencing 2MASS
    1. 2MASS Source Naming Convention
    2. Acknowledging 2MASS in Publications

II. Contents of the First 2MASS Incremental Data Release

  1. Properties of the Catalogs
    1. Point Source Catalog
      1. Selection Criteria
      2. General Photometric Properties
      3. Photometric Uncertainties
      4. Astrometric Uncertainties
    2. Extended Source Catalog
  2. Atlas Images
  3. Software
    1. hcompress
  4. Ancillary Files
    1. Point Source Record Format
    2. Extended Source Record Format
    3. Atlas Image Index
    4. Atlas Image Header Description
    5. Scan Corners File
    6. Known Asteroid Detection List
    7. SCAN DATABASE
  5. Initial Analysis Results

III. 2MASS Details

  1. Facilities
    1. Telescopes
    2. Camera and Detectors
    3. OBSERVATORY SITES AND SITE CONDITIONS
  2. Data Acquisition
    1. Scanning Strategy
    2. Survey Tiles (include MOON AVOIDANCE)
    3. Photometric Calibration Strategy
  3. Data Processing
    1. Instrumental Frame Correction
    2. Atlas Image Generation
    3. Point Source Detection and Photometry
    4. Band Merging and Bandfills
    5. Optical Source Associations
    6. Extended Source Identification and Photometry
    7. Position Reconstruction
    8. Artifact Identification
    9. Photometric Calibration
      1. Calibration Fields
      2. Global Calibration
      3. 2MASS PHOTOMETRY RELATIVE TO OTHER PHOTOMETRIC SYSTEMS
    10. Astrometric Registration and Calibration
    11. Catalog Generation
      1. REDUNDANT SOURCE RECTIFICATION
  4. Caveats and Limitations (in detail)
    1. Blah!
    2. Blah!!
    3. Blah!!!

This document prepared by R. Cutri, S. Van Dyk, and the 2MASS team.

Last modified 1999 Apr 19. For assistance, contact 2mass@ipac.caltech.edu