II. User's Guide to the WISE Preliminary Data Release
4. Ancillary Products
c. Atlas Image Frame Cross Reference Table
The WISE Preliminary Release Atlas Image Frame Cross Reference
Table provides a listing of all individual Single-exposure
image frames that contribute to each
Atlas Image in each band. It can be used
to determine which frames contribute to a given Atlas Image, or it can be
used to determine to which Atlas Images a particular Single-exposure image
The criteria used to select and filter the scans, framesets and frames that
are used as input for the Multiframe pipeline
processing that generates the coadded Atlas Images and extracted Source
Catalog are described in V.2.
i. Table Format Description
The following table contains brief descriptions of the parameters provided
for each record the WISE Preliminary Data Release Atlas Image Frame Cross
The columns in the following table are:
- Column Name: The parameter name in the Catalog table. Click on
this to go to the section of the Explanatory Supplement section in which
the derivation and/or usage of that parameter is described in greater
- Format: The ASCII-equivalent format of the field in the Catalog,
expressed in "C"-readable notation. This is useful when parsing
the aligned tabular output from
IRSA/Gator. Although the data
values will conform to these formats, the actual
width of the field in the Gator output may be padded with extra
blank spaces to accommodate column headers. Note that
some fields contain null values that will require special handling
when parsing Catalog tables from IRSA/Gator output.
- Units: The units of the parameter. A value of "----" in this
column means that the parameter is dimensionless or non-numeric.
- nulls: A "yes" in this column means this parameter
can be null in the Catalog. A "no" means there will always
be a value in this column in the Catalog.
- Description: A brief description of the parameter and its values.
|Column Name||Format||Units||nulls||Description|| |
|coadd_id||%20s||----||no||tlas Tile identifier from which source was extracted. The identifier
has the general form: RRRRsDDd_[trev], where
For example, the identifier of the Atlas Tile with center at
(α,δ = 304.13896,-13.63000) is 3041m137_aa11.
|band||%1d|| ---- ||no||WISE band number. 1=W1, 2=W2, 3=W3, 4=W4. || |
||Scan identifier. This is a six character string that identifies a block of
survey exposures that are acquired between two flight system maneuvers,
such as reorientation of the instrument boresite near the ecliptic poles,
or slews to acquire TDRSS for data downlink contacts. Because
maneuvers often take place near the ecliptic poles, the scan number
is roughly associated with a half-orbit's worth of images. However,
scans can cover less or more than half of the arc between ecliptic poles.
The scan_id has the general form SSSSSx, where
- SSSSS is a zero-filled, five-digit integer that is twice the WISE orbit number.
The orbit number increments each time the flight system passes the north
ecliptic pole (NEP). Orbit number 1 was defined to start with the fictitious
NEP passage immediately prior to WISE launch.
- x is a letter assigned based on sequential
count of scans started in a specific half-orbit. The first scan
has x="a", the next x="b", up to a maximum of x="d"
for scans in the Preliminary Release.
The first scan whose data are used in the Preliminary Data Release
is scan 00936a. This was the first scan after the NEP crossing
in the 468th WISE orbit. The final scan included in the Release is
04125a, the first scan after the SEP crossing in the 2062nd WISE orbit.
||Number of the frameset on which this source was extracted. The
identifier has the general form MMM, a zero-filled
The frameset number is computed based on time bins which count from the
scan start time:
fr_num = int[(((frame_utc - dt_beg) - scan_start_utc)/bin_size] + 1
- int means truncate to an integer
- frame_utc is the nominal frame exposure center UTC (when the boresite
crosses the image center) in seconds
- dt_beg is 4.4s. This is a nominal offset to approximate when
the exposure began
- scan_start_utc is the scan start time in seconds
- bin_size is 10s.
For example, a frame with a start time 1234 secs after the scan start
time would have a frame number of 124.
- Frame_num is not a frameset sequence number
- As a result of using a 10 sec bin, every 11th frame skips a number,
so it is normal to see breaks in the frame numbering and it doesn't
indicate missing data.
- Because frameset numbering is based on the predicted scan start time
from the survey plan, and because frameset data may not start being acquired
until well after the start of the scan, frameset numbers often do not
start at 1 for a scan.
||This is an internal archive accounting number that tracks in what batch
of data the information in this record were loaded into the database.
||Unique identification number for the Atlas Image Frame Cross Reference
table entry created sequentially in the order of the Archive load processing.
Last Updated: 2011 April 26
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