I. Introduction

9. Document Change History

The 2MASS All-Sky Data Release and Extended Mission Product Explanatory Supplement is a living document. It will updated regularly to provide users with the most current analyses and advice regarding 2MASS Data Products. The most up-to-date version of the Supplement is always accessible as a hypertext document at http://www.ipac.caltech.edu/2mass/releases/allsky/doc/explsup.html.

This page documents by date changes to the Supplement since the initial publication on March 25, 2003.

• 2003 March 25 - Explanatory Supplement Initial Publication Date.

• 2003 Apr 2
  • Modified section II.2b to standardized format; the thrust of the text in this subsection is unchanged.

• 2003 Apr 8
  • Modified section III.1a to standardized format; the thrust of the text in this subsection is unchanged.
  • "Ported over" section VI.1 from M. Skrutskie's site to the local site of the Supplement and modified to standardized format.

• 2003 Apr 14
  • Inserted section II.6, key to the ancillary files.
  • Added Scan Information Table, linked to section II.6.

• 2003 Apr 17
  • Added section II.6h, updates to the All-Sky DVD-ROM release.

• 2003 May 2
  • Brought over and adapted subsections of VI.1 to local server.

• 2003 May 5
  • Revised values in Table 1 of section VI.4a.
  • Transferred and adapted section VI.4b to local server.
  • Transferred and adapted subsections of VI.5 to local server.
  • Transferred and adapted section VI.6b to local server.
  • Transferred and adapted section VI.7 to local server.

• 2003 May 19
  • Inserted text describing unreliable optical associations for point sources with |dec|>86° in sections I.6b, II.2a, and IV.4f.

• 2003 Jul 1
  • Included caveat in sections I.6b, II.2a, and IV.4f for incorrect "a" values for optical associations with dist_opt > 5´´ in the PSC.

• 2003 Oct 3
  • Modified all references to an anticipated date in 2003 for the online release of the non-lossy-compressed All-Sky Atlas Images to an unspecified, later date.

• 2004 Jun 7
  • Revised version of Tables 2 and 2a for Section III.2.c. Also, a revised version of Table 3 and the installation of Table 3a for this section.

• 2004 Jul 1
  • Revised order of column headings for Table 2 in Section VI.2 from "Band," "Mean," "Min," "Max," "Std.Dev." to "Band," "Min," "Max," "Mean," "Std.Dev."

• 2004 Aug 20
  • Corrected the values for the physical and effective gaps in the Survey sky coverage in Section III.2.c.
  • Amended the descriptions of the XSC parameters, j_phi, h_phi, k_phi, and sup_phi in Section II.3.a.

• 2004 Sep 7
  • Updated Sections I.3, I.6d, and II.4 to reflect availability of the All-Sky Atlas Images via the IRSA services.

• 2004 Sep 21
  • Added Section VI.6c on band-frame distortion.

• 2004 Dec 16
• Minor corrections to descriptions of the XSC parameters r_k20fe, r_fe, r_k20fc, r_fc, r_j21fe, r_j21fc in Section II.3.a.
• 2004 Dec 21
• Updates to Large Galaxy Atlas links in Section I.6.c.
• 2004 Dec 29
• Added reference to mch_cnf parameter to Known Asteroid and Comet association procedure discussion in Section IV.9.a.
• 2005 June 7
• Update links to PLEXUS software in Sections III.1.b1 and VI.6.a
• 2005 October 12
• Added table of Calibration Fields and field center positions to Section III.2.d.
• Miscellaneous typographical errors corrected in Sections IV.8 and VI.2.
• 2005 December 5
• Section IV.2.e added describing non-linearity/saturation characterization and handling in data reduction pipeline.
• Miscellaneous wording changes and typographical errors corrected in Sections IV.2.a-d.
• 2006 May 4
• Added section VI.8.a describing error estimation from photometric measurements made using 2MASS Atlas Images.
• Added caution about photometric error estimation and link to section VI.8.a in Atlas Image Cautionary Notes section I.6.d.
• 2006 October 10
• Updated section IV.3 to indicate correct blank coverage pixel value in the Atlas Images (NaN).
• 2006 November 21
• Corrected "units" of the [jhk]_snr column descriptions in section II.2.a to indicate that these parameters are dimensionless.
• 2006 December 18
• Miscellaneous typographical corrections and link updates to Section II.2.a.
• Made link to 2MASS optical component and full system transmission description page more prominent in Section III.1.b.
• 2006 December 20
• Extended Mission Ancillary Product description initial publication in Appendices 1-7.
• 2007 January 12
• Updated discussion of chance association between background inertial sources and solar system objects in section IV.9.b.
• 2007 December 28
• Updated links to external report on residual diffraction spike detection artifacts in the All-Sky PSC in sections I.6.b and IV.7.b.
• 2008 March 12
• Updates to multiple sections in support of Extended Mission LMC/SMC 6x and Calibration field data release: A1.1, A1.2, A1.4.b, A1.4.c, A3.1, A3.1.d, A3.2, A4.1, A4.1.c, A4.2, A4.3.a, A4.3.b, A4.4, A6.1, A7.1, A7.4, A7.5.
• Added discussion of duplicate sources in the 6x-PSC caused by confusion in multiple source resolution process to sections A3.1.d, A3.6.d.
• 2008 September 3
• Added 2MASS Hardware and Operations Significant Events Log as Table 4 in section III.1.b.
• 2008 September 7
• Added section VI.9 describing photometric bias in southern J-band photometry for sources that fall on the central detector column.
• 2008 December 28
• Updated description of RSR curves in VI.4.a to be consistent with that given by Cohen et al. (2003).

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