The Two Micron All Sky Survey (2MASS)

TLDR

The Two Micron All Sky Survey (2MASS) acquired 25.4 TB of near‑infrared imaging from 1997 to 2001 using two 1.3‑m telescopes at Mount Hopkins and Cerro Tololo, covering 99.998 % of the sky with 7.8‑s integrations in J, H, and Ks bands and achieving 10σ point‑source limits of 15.8, 15.1, and 14.3 mag. The All‑Sky Data Release delivers 4.1 million compressed FITS images, 471 million point‑source catalog entries, and 1.6 million extended‑source entries, with photometric precision better than 0.03 mag, astrometric accuracy around 100 mas, and inter‑point calibration offsets below 0.02 mag.

Abstract

Between 1997 June and 2001 February the Two Micron All Sky Survey (2MASS) collected 25.4 Tbytes of raw imaging data covering 99.998% of the celestial sphere in the near-infrared J (1.25 μm), H (1.65 μm), and Ks (2.16 μm) bandpasses. Observations were conducted from two dedicated 1.3 m diameter telescopes located at Mount Hopkins, Arizona, and Cerro Tololo, Chile. The 7.8 s of integration time accumulated for each point on the sky and strict quality control yielded a 10 σ point-source detection level of better than 15.8, 15.1, and 14.3 mag at the J, H, and Ks bands, respectively, for virtually the entire sky. Bright source extractions have 1 σ photometric uncertainty of <0.03 mag and astrometric accuracy of order 100 mas. Calibration offsets between any two points in the sky are <0.02 mag. The 2MASS All-Sky Data Release includes 4.1 million compressed FITS images covering the entire sky, 471 million source extractions in a Point Source Catalog, and 1.6 million objects identified as extended in an Extended Source Catalog.