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2MASS Calibration Merged Point Source Information Table

Metadata Updated: April 10, 2026

Photometric calibration for 2MASS was performed using observations of calibration fields made at regular intervals during each night of survey operations. Measurements of standard stars in the fields were used to derive the photometric zero point offsets as a function of time during each night. Atmospheric extinction coefficients were derived from 2MASS observations made over long periods.\n\n2MASS calibration fields, or tiles, are 1° long in declination and approximately 8.5' wide in right ascension. There are 35 regular survey calibration fields distributed at approximately two hour intervals in right ascension near declinations of approximately -30°, 0° and +30°. An additional five calibration fields were defined in and around the Large and Small Magellanic Clouds to support the deep observation (6x) campaign towards the end of survey operations.\n\nOver the course of the survey, the regular calibration fields were scanned between 562 and 3692 times in nominally photometric conditions. Equatorial fields were observed from both observatories, so were observed more frequently than those near ±30° which were observed with only one telescope. The special Magellanic Cloud calibration fields were observed 108 to 468 times between November 2000 and February 2001.\n\nThe following table contains brief descriptions of the entries in the Survey, 6x and Calibration Merged Point Source Information Tables. The merged source tables contain the mean positions magnitudes and uncertainties for sources detected multiple times in each of the 2MASS data sets. The merging was carried out using an autocorrelation of the respective databases to identify groups of extractions that are positionally associated with each other, all lying within a 1.5" radius circular region. A number of confirmation statistics are also provided in the tables that can be used to test for source motion and/or variability, and the general quality of the merge.

Access & Use Information

Public: This dataset is intended for public access and use. License: See this page for license information.

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Dates

Metadata Created Date April 11, 2025
Metadata Updated Date April 10, 2026

Metadata Source

Harvested from NASA Data.json

Additional Metadata

Resource Type Dataset
Metadata Created Date April 11, 2025
Metadata Updated Date April 10, 2026
Publisher NASA/IPAC Infrared Science Archive
Maintainer
Identifier ivo://irsa.ipac/2mass/catalog/calmpsit
Data Last Modified 2026-04-06
Category Astrophysics
Public Access Level public
Bureau Code 026:00
Metadata Context https://project-open-data.cio.gov/v1.1/schema/catalog.jsonld
Schema Version https://project-open-data.cio.gov/v1.1/schema
Catalog Describedby https://project-open-data.cio.gov/v1.1/schema/catalog.json
Harvest Object Id 62baa453-59a6-4d3a-92da-a8882d2c8d7a
Harvest Source Id 58f92550-7a01-4f00-b1b2-8dc953bd598f
Harvest Source Title NASA Data.json
Homepage URL ivo://irsa.ipac/2mass/catalog/calmpsit
License https://www.usa.gov/government-works
Program Code 026:000
Source Datajson Identifier True
Source Hash 1f0af0da6b95302aa15af23cb53e41c61cadff59754fef4640d9dbfee1072dcb
Source Schema Version 1.1

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