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).

Table 1 - Combined Calibration Scan Image and Source List Access
GeneralCombined Image DataSource Extractions
Tilera(J2000)dec(J2000)glonglatNscnNJ(N/S)NH(N/S)NK(N/S)full
images
masked
images
BrowseSource ListProperties
9002116.10619-1.97294107.36651-64.025232025875/873873/872907/906 (45MB) (38MB)XX
902948.31622-39.40154318.91629-77.1572626211208/12081208/12071207/1207 (45MB) (38MB)XX
90299211.25260-70.58353303.70812-46.53497468217/217217/217217/217
(32MB)

(28MB)
X (N/A)X
9000428.66074+0.71693154.11677-58.2752729771393/13911404/14051411/1412 (44MB) (36MB)XX
9030151.72678-39.84268244.63466-55.5063834301627/16281627/16281627/1628 (43MB) (36MB)XX
9024753.01617+37.34386155.04346-15.317521962885/900885/899888/904 (46MB) (41MB)XX
9053355.26392+6.93647179.51313-36.676091839851/847851/847860/855 (45MB) (38MB)XX
90191366.58918+3.62342190.90892-29.778102086979/973979/973979/974 (45MB) (38MB)XX
90400474.90247-65.73341276.28631-35.95631378166/166166/166166/166
(39MB)

(30MB)
X (N/A)X
90401478.62001-71.00065282.10956-33.3734643275/7575/7575/75
(37MB)

(30MB)
X (N/A)X
9001389.28447+0.01890206.63167-12.0488535151631/16261632/16241631/1624 (47MB) (38MB)XX
90402493.56589-69.66665279.95935-28.52288156196/197196/197196/197
(37MB)

(28MB)
X (N/A)X
9012197.37444-59.65713268.95105-25.88052562267/266266/267266/267 (38MB) (40MB)XX
90161105.22232+48.48935168.28907+21.4552925931170/11711169/11711205/1209 (48MB) (42MB)XX
90312126.40319-39.09847257.57412-0.6689535011655/16511654/16501654/1649 (50MB) (46MB)XX
920265128.12790-1.57084226.54812+21.5465621581019/10191018/10181017/1017 (45MB) (39MB)XX
900676132.81203+11.84773215.63879+31.9047436921698/17061695/17051695/1705 (50MB) (43MB)XX
90091145.75214+59.06160154.88828+44.63064789369/369369/369369/369 (42MB) (39MB)XX
923977170.45775-13.22047271.78770+44.1655325851195/11991193/11971193/1197 (46MB) (39MB)XX
90217180.44070-50.05148294.81518+12.035801687796/795796/794796/795 (46MB) (43MB)XX
90266183.61047+35.59855163.59937+78.4311427761299/12991299/12991305/1305 (46MB) (39MB)XX
90860185.41757-0.12034287.00945+61.8276324521087/10781075/10681075/1066 (44MB) (37MB)XX
90867220.24529-0.45767351.08190+51.86698949453/447453/446453/446 (44MB) (39MB)XX
90273224.21932-44.81900325.15505+12.572201780832/841832/840832/841 (48MB) (45MB)XX
90272224.64303+37.1417361.47581+61.447771973898/901898/901923/926 (44MB) (38MB)XX
908688225.11368-0.65787356.36663+48.3629121861029/10271029/10271029/1027 (46MB) (39MB)XX
90565246.68168+5.8718520.52082+34.6977533961545/15511545/15501588/1593 (47MB) (39MB)XX
900099246.80780-24.68901352.96954+16.584651582749/752749/752748/752 (47MB) (44MB)XX
90330247.89420+30.1455250.25044+42.070851192564/564564/564564/564 (42MB) (38MB)XX
90279267.09736-45.42783346.06515-8.92593977461/464462/464461/464 (47MB) (46MB)XX
90182279.89627+49.0936378.07393+22.009071703728/728727/729755/755 (47MB) (42MB)XX
9054710282.82780-4.2748829.11141-1.91959671270/278270/277279/286 (47MB) (50MB)XX
90808285.48438-4.4879430.12525-4.376621876848/850847/850850/853 (52MB) (49MB)XX
90234307.83812-49.64775349.60727-36.216312076981/981981/981981/981 (44MB) (38MB)XX
90813310.27504-5.0633941.33281-26.642991570699/708699/707719/721 (46MB) (41MB)XX
9240911330.11998+20.8496277.72803-26.650881439654/650654/650666/662 (44MB) (27MB)XX
9220212331.40247-11.0747747.13268-47.9166928021318/13181318/13181318/1318 (45MB) (37MB)XX
90893349.54575+0.5485780.12434-54.3819926191200/11991200/11991225/1223 (47MB) (40MB)XX
90290352.64369+38.31591105.94466-21.873691141564/565564/565567/568 (45MB) (41MB)XX
902982356.63061-74.50079308.68978-41.8938110852/5252/5252/52
(32MB)

(28MB)
X (N/A)X

Column descriptions for Table 1

[Last Updated: 2008 February 18; by R. Cutri]


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