BITPIX value | Data representation | Scaling | MIDAS data type |
8 | 8-bit unsigned integer (ASCII) | No | D_I1_FORMAT |
Yes | D_R4_FORMAT | ||
16 | 16-bit twos-complement integer | No | D_I2_FORMAT |
Yes | D_R4_FORMAT | ||
32 | 32-bit twos-complement integer | No | D_I4_FORMAT |
Yes | D_R4_FORMAT | ||
-32 | 32-bit IEEE floating point | - | D_R4_FORMAT |
-64 | 64-bit IEEE floating point | - | D_R8_FORMAT |
Each HDU in a FITS file will normally correspond to a single MIDAS
file. HDU's with no associated data are not stored. Besides the prime
HDU which either is a simple data matrix or a random group structure a
number of extension are defined. Currently, the extensions listed in
Table 7.1.2 are translated by MIDAS whereas other 'unknown'
extensions are skipped. Text and MIDAS-fit files can also be
stored in FITS. The content of these file types is stored as FITS
headers using a special MIDAS conversion. Thus, other FITS readers may
not be able to retrieve the full information.
FITS Extension type | MIDAS frame | |
prime | image (.bdf) | |
random groups | image (.bdf) + table (.tbl) | |
TABLE | table (.tbl) | |
BINTABLE | table (.tbl) | |
IMAGE | image (.bdf) |