I. Introduction

5. Data Release Plan

a. The 2MASS Sampler

The 2MASS Sampler (1998 December), was the first release of 2MASS data to the community. The Sampler included data from one night (1997 Nov 16 UT) obtained at the northern 2MASS facility on Mt. Hopkins.

b. The 2MASS Incremental Data Releases

The 2MASS 1999 Spring Data Release (May 1999) was the first of the large "Incremental" issues of Survey data products. This new release, is the second such issue. The Incremental releases include the Catalogs and Image products produced from data processing performed while Survey observations are ongoing. Their scope includes survey data acquired and/or processed each consecutive 6-12 months during the Survey; the phase lag between data acquisition and initial release will decrease as the Survey progresses. The Second Incremental Data Release includes the data from the 2MASS Sampler and First Incremental (Spring 1999) Releases, and is intended to supersede those releases. Future Incremental Releases are expected to be "differential", adding to growing Point and Extended Source Catalogs produced from previous release with possible small changes to the previous versions.

The Second Incremental Release was originally scheduled to occur in the Fall of 1999, and to include data covering 20-25% of the sky. However, because data processing was sufficiently advanced it was possible to double the area covered by the release, with only a small delay in the release schedule. The scope of this new release is now ~47% of the sky.

Further 2MASS Incremental releases are scheduled approximately every 6-12 months until shortly after the end of Survey data acquisition. Please see the main 2MASS web pages for announcements of further releases.

The 2MASS Incremental release data are representative of the scope and quality of the final data products, but should still be viewed as preliminary products because they do not benefit from all experiences that will be gained over the full Survey. In particular, the Incremental release data have not benefitted from the analyses of the full-sky dataset, nor have they undergone all the rigorous analyses that accompany data releases at the end of mission.

c. The 2MASS Final Products Release

Following the end of 2MASS Survey operations and the release of the last Incremental data products, the full set of raw data will undergo a complete reprocessing. The reprocessing is intended to allow an opportunity to improve processing algorithms, adapt to challenges found in the data, and to incorporate global information obtained over the life of the Survey and from the analyses of global relationships in the data. The 2MASS Final Catalogs and Image Products will be released following this complete reprocessing.

N.B.: The final reprocessing has been completed and the Final Data Release is pending. (Note added 2002 June 27.)

[Last Update: 1999 December 20; R. Cutri]

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