Appendix 7. Combined Calibration Scan Images and Source Lists
4. Combined Calibration Scan Data Access
The Combined 2MASS Calibration Scan Images and Source Lists were produced
by averaging together the best images of each calibration field
and performing conservative source detection on the resulting images. The
total exposure times accumulated for the calibration fields range from one
to eight hours, so the combined calibration scan images reach 3.5 to 4.5
magnitudes deeper than single scans in the absence of confusion.
These images and source lists represent the deepest measurements
made possible by 2MASS.
An overview of the Combined Calibration Scan Image and Source
Data, the image generation and source extraction process is given in
Appendix 7 of the on-line
2MASS Explanatory Supplement.
Users are strongly recommended to review the
Cautionary Notes
concerning the limitations and features of the Combined Calibration
Scan Images and Source Lists before using them.
You may retrieve the images and source lists for each 2MASS calibration
field interactively using the table below.
The "General" columns provide the calibration tile number
(click on the tile number to view a 3-color JPEG preview image
of the combined image of the field), the central position of
the field, and the number of times it was scanned under photometric
conditions during the survey. Clicking on the blue or green
buttons under the "Combined Image Data" sections enables ftp transfer
of the full-field images, or the images that are masked to
show only pixels covered by >30% of the available scans, respectively.
The "Source List" button is linked to the ascii format extracted
source lists for the field. The red "Browse" button will display a
listing of the file directory for each field, allowing you to
retrieve individual images. The format of
the source lists is described in A7.3.d.
The "Properties" column links to summaries of the image
and source list characteristics for each field, including
areal coverage, source counts, noise distributions, color-magnitude
and color-color plots, and astrometric and photometric
comparisons with the 2MASS All-Sky Point Source Catalog
(see also A7.5).
Column descriptions for Table 1
[Last Updated: 2008 February 18; by R. Cutri]
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