I. Introduction

4. Distribution Mode for 2MASS Products

a. On-Line Access

The primary mode of access to the 2MASS First Incremental Data Release products is via the on-line services of the NASA/IPAC Infrared Science Archive (IRSA) services.

Catalogs:
Logical queries on the First Release PSC and XSC can be made via the "CATSCAN" on-line tool. CATSCAN allows the Catalogs to be searched by specifying position, brightness, or a number of other constraint. Both a simple "Query-by-Table" interface or a more flexible direct-SQL query input mode can be utilized to search the catalogs.
Note - CATSCAN is not designed to support full-downloads of the First Release Catalogs

Atlas Images:
FITS format images from the 2MASS First Release Image Atlas may be retrieved using the IRSA 2MASS Survey Visualization and Image Server service. Images may be requested on the basis of input coordinates or object names. Users may obtain full J, H and K_sAtlas Images, or a specified subimages.
Note - The 2MASS Survey Visualization and Image Server returns FITS images that are expanded from lossy-compressed Atlas Images. Photometry from the PSC and XSC should always take precedent of photometry from these images.

Extended Source "Postage Stamp" Images

Full-resolution, background-subtracted images centered on objects contained in the 2MASS First Release XSC can be retrieved using the IRAS 2MASS Extended Source Full-Resolution Image Server . Users may specify the coordinate of the 2MASS XSC source, or object name, and the service returns the J, H and K_s postage stamps, along with a 3-color image of the source, and basic catalog information.

Coordinate Coverage Search Tool

The 2MASS Coordinate Coverage Check tool allows user to determine if an equatorial position of interest is included in the First Incremental Data Release area.

b. Electronic Access to Full Catalogs

The 2MASS First Release Catalogs and Scan Information Table may be retrieved in compressed ascii form via anonymous ftp. File compression was done using gzip.

Users should be aware that the catalog tables are extremely large. The largest table, the PSC, has been broken into eight sections for convenience, but each compressed section is still ~240 MB in size. Uncompressed the PSC occupies a total of 7.72 GB. The table below summarizes the tables available via ftp and their sizes.

2MASS Catalogs and Tables available via anonymous ftp:


File       No.Records     StartRA       EndRA  Full Size    Comp.Size
--------------------------------------------------------------------
ptsrc1.tbl    2525548    1.369038   68.991717  964760978    246312030
ptsrc2.tbl    2525548   68.991800   88.833294  964760978    243604108
ptsrc3.tbl    2525548   88.833307  100.346687  964760978    243698060
ptsrc4.tbl    2525548  100.346702  188.939536  964760978    245040821
ptsrc5.tbl    2525548  188.939745  287.908680  964760978    236302582
ptsrc6.tbl    2525548  287.908681  293.691041  964760978    230860434
ptsrc7.tbl    2525547  293.691043  297.715792  964760596    233815842
ptsrc8.tbl    2525543  297.715795  359.398120  964759068    239309695

extsrc.tbl      73980    1.375096  359.393768  243111538     45437467

scaninfo.tbl     3391    1.438408  359.327857    1378408       347990

FTP Retrieval Instructions:

% ftp anon-ftp.ipac.caltech.edu

     [Login as anonymous, use your email address as the password]
     Name (anon-ftp:) anonymous
     Password:  [your email address]

ftp> cd /pub/2mass/idr1

ftp> dir  [To list file names]
ftp> binary
ftp> get [filename]
...
...
ftp> bye

or, access via the Web at ftp://anon-ftp.ipac.caltech.edu/pub/2mass/idr1/.

c. DVD-ROM Catalog Versions

A DVD-ROM containing the 2MASS First Release PSC and XSC is available. If you are interested in ordering this product, please fill out the order form. Quantities and availability are limited.

[Last Update: 2000 May 8; R. Cutri]

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