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The RI is the fundamental input for NEWSIPS. For the final archive,
the original GO format RIs have been converted to FITS. Although the
RI data remains unaltered, the VICAR label has been converted to FITS
commentary keywords (including the conversion of the binary information
to hexadecimal ASCII characters).
The RILO/RIHI contain a two-dimensional (2-D) primary array consisting
of
768 × 768 pixels. Each pixel is a data number (DN), coded as
an 8-bit unsigned integer ranging from 0 to 255. The basic keywords are
shown in Table 12.4.
During the preparation of input data for Final Archive processing, it
was discovered that some low-dispersion partial read images were not
properly registered for processing. These raw images are therefore
shifted to put them into proper registration for future processing by
NEWSIPS. In order to preserve the original (unaltered) data, the RILO
contain both the corrected data in the primary array and the original
unshifted RI data in an image extension. The format of the image
extension data is identical to that described above for the primary
array. Note that the RIHI are not affected, and in low dispersion only
the corrected data, in the primary array, is used for further processing
by NEWSIPS. The basic keywords for partial-read files are shown in
Table 12.5.
Table 12.4:
RILO/RIHI - Basic FITS Keywords
| Keyword and value |
Description |
|---|
SIMPLE = T |
Standard FITS Format |
BITPIX = 8 |
8-bit integer pixels |
NAXIS = 2 |
Two-dimensional image |
NAXIS1 = 768 |
Dimension along x-axis |
NAXIS2 = 768 |
Dimension along y-axis |
CTYPE1 = 'SAMPLE ' |
x-axis |
CTYPE2 = 'LINE ' |
y-axis |
BUNIT = 'DN ' |
Data Numbers |
TELESCOP= 'IUE ' |
International Ultraviolet
Explorer |
FILENAME= 'AAAnnnnn.RIdd' |
Filename (camera)(number).RI(disp) |
DATE = 'dd/mm/yy' |
Date file was written |
ORIGIN = 'VILSPA ' |
Institution generating the file |
DATAMIN = nnn.0 |
Minimum pixel value |
DATAMAX = nnn.0 |
Maximum pixel value |
Table 12.5:
RILO Partial Read - Basic FITS Keywords
| Keyword and value |
Description |
|---|
SIMPLE = T |
Standard FITS Format |
BITPIX = 8 |
8-bit integer pixels |
NAXIS = 2 |
Two-dimensional image |
NAXIS1 = 768 |
Dimension along x-axis |
NAXIS2 = 768 |
Dimension along y-axis |
EXTEND = T |
Extension exists |
CTYPE1 = 'SAMPLE ' |
x-axis |
CTYPE2 = 'LINE ' |
y-axis |
BUNIT = 'DN ' |
Data Numbers |
TELESCOP= 'IUE ' |
International Ultraviolet
Explorer |
FILENAME= 'AAAnnnnn.RILO' |
Filename (camera)(number).RI(disp) |
DATE = 'dd/mm/yy' |
Date file was written |
ORIGIN = 'VILSPA ' |
Institution generating the file |
DATAMIN = nnn.0 |
Minimum pixel value |
DATAMAX = nnn.0 |
Maximum pixel value |
XTENSION= 'IMAGE ' |
Image extension |
BITPIX = 8 |
Binary data |
NAXIS = 2 |
Two-dimensional image |
NAXIS1 = 768 |
Dimension of x-axis |
NAXIS2 = 768 |
Dimension of y-axis |
PCOUNT = 0 |
number of bytes following data
matrix |
GCOUNT = 1 |
number of groups |
CTYPE1 = 'SAMPLE ' |
x-axis |
CTYPE2 = 'LINE ' |
y-axis |
BUNIT = 'DN ' |
Data Numbers |
FILENAME= 'AAAnnnnn.ROLO' |
Filename (camera)(number).RO(disp) |
EXTNAME = 'RISV ' |
Original raw image |
Next: 12.4 Linearized Image FITS
Up: 12 Final Archive Data
Previous: 12.2.4.2 High-dispersion Header Example
Karen Levay
12/4/1997