I. Introduction
4. Distribution Mode for 2MASS Products
a. On-Line Access
The primary mode of access to the 2MASS Second Incremental Release products is via the on-line services of the NASA/IPAC Infrared Science Archive (IRSA).
- Catalogs:
Logical queries on the Second Incremental Release Catalogs and Tables can be made via the "Basic Catalog Search" and "GATOR" on-line tools. These tools allow the Catalogs to be searched by specifying constraints on position, brightness and other parameters, or combinations thereof. The Basic Catalog Search tool is limited to simple position, brightness and color queries on the Catalogs, while GATOR offers a more flexible "Qeury-By-Table" and user-customizable SQL query input modes to search any of the Release data tables.
Note - GATOR is not designed to support full-downloads of the 2MASS Catalogs. Please see section I.4.b and I.4.c, below.
- Atlas Images:
FITS format images from the 2MASS Second Incremental Release Image Atlas may be retrieved using the IRSA 2MASS Survey Visualization and Image Server and 2MASS Image Retrieval Service tools.
The IRSA/2MASS Survey Visualizer allows users to view and download the full or subsetted 2MASS "Quicklook" Atlas Image in the J, H and/or Ks bands, that contains a specified input coordinate or source name. This service provides the fastest access for small numbers of images. The "Quicklook" images are expanded from lossy-compressed Atlas Images.
Important Note - The "Quicklook" Images returned by 2MASS Survey Visualization and Image Server are FITS images that are expanded from lossy-compressed Atlas Images. These images must not be used to make quantitative brightness measurements of point or extended sources. Please refer to the Source Catalogs for source photometry.
- The IRSA/2MASS Batch Image Retrieval Service allows batch-mode
retrieval of both the full-resolution (non-compressed) 2MASS Atlas Images
and the 2MASS "Quicklook" Images (expanded from lossy-compressed images).
Users may specify the Images to be retrieved in one of two ways: 1) all
images falling within a specified radius around an input coordinate or source
name, or 2) the full or subsetted images containing coordinates or source names
provided in an uploaded list.
The batch Image Retrieval Service
is designed only for Image downloads, and does not have any viewing
capability.
2MASS lossy-compressed "Quicklook" Images are stored locally on spinning disk and retrieval times generally range from a few seconds to minutes. The non-compressed Atlas Images are retrieved via high speed link from the the High Performance Storage System (HPSS) at the San Diego Supercomputing Center (SDSC), a national research resource developed and operated by SDSC under the National Partnership for Advanced Computional Infrastructure (NPACI) program funded by National Science Foundation (NSF). Nominal retrieval times for the remotely stored Atlas Images should be less than 20 minutes.
- Extended Source "Postage Stamp" Images
- Coordinate Coverage Search Tool
Full-resolution, background-subtracted images centered on
objects contained in the 2MASS Second Incremental XSC can be retrieved
using the IRAS 2MASS Extended Source Image Server .
Users may specify the coordinate of the 2MASS XSC source, or object
name, and the service returns the J, H and Ks postage
stamps, along with a 3-color image of the source, and basic catalog
information.
The 2MASS
Coordinate Coverage Check tool allows user to determine if an equatorial
position of interest is included in the Second Incremental Release
area.
b. Electronic Access to Full Catalogs
The 2MASS Second Incremental Release Catalogs and Scan Information Tables may be retrieved in compressed (gzipped) ascii form via anonymous ftp.
Users should be aware that the catalog tables are extremely large. The largest table, the PSC, has been divided into 49 right ascension segments. Within each segment, source entries are ordered by increasing declination. Uncompressed the PSC occupies a total of 49 GB. The table below summarizes the tables available via ftp and their sizes.
2MASS Catalogs and Tables available via anonymous ftp: File RAmin RAmax No.Records Full Size Compressed Size Name (hours) (hours) (bytes) (bytes) ----------------------------------------------------------------------- idr2psc0.tbl >=00.000 <01.000 2629609 794231612 237720473 idr2psc1.tbl 01.000 02.000 2252758 680332916 204719934 idr2psc2.tbl 02.000 03.000 2493743 753110386 225923981 idr2psc3.tbl 03.000 04.000 3136506 947224812 284649102 idr2psc4.tbl 04.000 05.000 4604210 1390471420 414649441 idr2psc5a.tbl 05.000 05.500 3628578 1095830556 321476034 idr2psc5b.tbl 05.500 06.000 4855844 1466464888 430761436 idr2psc6a.tbl 06.000 06.250 2697340 814596680 236534416 idr2psc6b.tbl 06.250 06.500 2683592 810444784 236383132 idr2psc6c.tbl 06.500 06.750 2859875 863682250 252505447 idr2psc6d.tbl 06.750 07.000 2981199 900322098 262867550 idr2psc7a.tbl 07.000 07.250 3452852 1042761304 304158750 idr2psc7b.tbl 07.250 07.500 2801843 846156586 246548604 idr2psc7c.tbl 07.500 07.750 3424224 1034115648 302234795 idr2psc7d.tbl 07.750 08.000 3270702 987752004 287806108 idr2psc8a.tbl 08.000 08.500 4386523 1324729946 389061071 idr2psc8b.tbl 08.500 09.000 2369286 715524372 211675836 idr2psc.tbl9 09.000 10.000 1789707 540491514 164046068 idr2psc10.tbl 10.000 11.000 1680899 507631498 152054351 idr2psc11.tbl 11.000 12.000 1200593 362579086 110526889 idr2psc12.tbl 12.000 13.000 1363189 411683078 125153115 idr2psc13.tbl 13.000 14.000 1587656 479472112 144375906 idr2psc14.tbl 14.000 15.000 1652704 499116608 151110418 idr2psc15.tbl 15.000 16.000 2401613 725287126 218603997 idr2psc16a.tbl 16.000 16.500 3462252 1045600104 304894177 idr2psc16b.tbl 16.500 17.000 3880645 1171954790 342635465 idr2psc17a.tbl 17.000 17.125 1829700 552569400 156951524 idr2psc17b.tbl 17.125 17.250 2174252 656624104 184991627 idr2psc17c.tbl 17.250 17.375 2185469 660011638 181257904 idr2psc17d.tbl 17.375 17.500 2927724 884172648 241019777 idr2psc17e.tbl 17.500 17.625 3885799 1173511298 319418104 idr2psc17f.tbl 17.625 17.750 4274522 1290905644 353216064 idr2psc17g.tbl 17.750 17.875 4237587 1279751274 351766146 idr2psc17h.tbl 17.875 18.000 3589489 1084025678 295545643 idr2psc18a.tbl 18.000 18.250 5660571 1709492442 472688518 idr2psc18b.tbl 18.250 18.500 4038453 1219612806 343956738 idr2psc18c.tbl 18.500 18.750 5199964 1570389128 445002850 idr2psc18d.tbl 18.750 19.000 4807890 1451982780 419144957 idr2psc19a.tbl 19.000 19.250 4018277 1213519654 346222437 idr2psc19b.tbl 19.250 19.500 5146644 1554286488 440144439 idr2psc19c.tbl 19.500 19.750 6526988 1971150376 561063072 idr2psc19d.tbl 19.750 20.000 5088333 1536676566 438686697 idr2psc20a.tbl 20.000 20.250 4026153 1215898206 344520919 idr2psc20b.tbl 20.250 20.500 3438208 1038338816 293995418 idr2psc20c.tbl 20.500 20.750 2643747 798411594 227040960 idr2psc20d.tbl 20.750 21.000 1662519 502080738 144571786 idr2psc21.tbl 21.000 22.000 5309666 1603519132 472892553 idr2psc22.tbl 22.000 23.000 3615167 1091780434 325742477 idr2psc23.tbl 23.000 24.000 2377993 718153886 215351715 idr2xsc.tbl 0.000 24.000 585056 1409984960 320389145 idr2scan.tbl 0.000 24.000 27493 10612298 2881978
FTP Retrieval Instructions:
% ftp ftp.ipac.caltech.edu
[Login as anonymous, use your email address as the password] Name (anon-ftp:) anonymous Password: [your email address]
ftp> cd /2mass/idr2
ftp> dir [To list file names] ftp> binary ftp> get [filename] ... ... ftp> bye
or, access via the Web at ftp://ftp.ipac.caltech.edu/2mass/idr2/.
c. DVD-ROM Catalog Versions
A limited number of DVD-ROMs containing the 2MASS Second Incremental Release Catalogs and Tables have been produced. Note that these disks contain only the Catalog Tables and are intended for use by professional astronomers and institutions. The DVD does not contain the Image Atlas. If you are interested in ordering this product, please fill out the order form.
[Last Update: 2004 August 15; R. Cutri, further revisions by S. Van Dyk.]
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