Converts an IRCAM data file to a series of NDFs


This applications converts an HDS file in the IRCAM format listed in IRCAM User Note 11 to one or more NDFs. See the "Notes" for a detailed list of the rules of the conversion.


ircam2ndf in prefix obs [config]


The choice of data array to place in the NDF. It can have one of the following configuration values:
  • "STARE" — the image of the object or sky;
  • "CHOP" — the chopped image of the sky;
  • "KTCSTARE" — the electronic pedestal or bias associated with the stare image of the object or sky;
  • "KTCCHOP" — the electronic pedestal or bias associated with the chopped image of the sky.

Note that at the time of writing chopping has not been implemented for IRCAM. For practical purposes CONFIG="STARE" should be used. The suggested default is the current value. ["STARE"]

This specifies whether or not format conversion may occur. If FMTCNV is FALSE, the data type of the data array in the NDF will be the same as that in the IRCAM file, and there is no scale factor and offset applied. If FMTCNV is TRUE, whenever the IRCAM observation has non-null scale and offset values, the observation data array will be converted to type _REAL in the NDF, and the scale and offset applied to the input data values to give the ‘true’ data values. A null scale factor is 1 and a null offset is 0. [FALSE]
IN = IRCAM (Read)
The name of the input IRCAM file to convert to NDFs. The suggested value is the current value.
OBS() = LITERAL (Read)
A list of the observation numbers to be converted into NDFs. Observations are numbered consecutively from 1 up to the actual number of observations in the IRCAM file. Single observations or a set of adjacent observations may be specified, e.g. entering [4,6-9,12,14-16] will read observations 4,6,7,8,9,12,14,15,16. (Note that the brackets are required to distinguish this array of characters from a single string including commas. The brackets are unnecessary when there is only one item.)

If you wish to extract all the observations enter the wildcard . 5- will read from 5 to the last observation. The processing will continue until the last observation is converted. The suggested value is the current value.

The prefix of the output NDFs. The name of an NDF is the prefix followed by the observation number. The suggested value is the current value.


ircam2ndf ircam_27aug89_1cl rhooph obs=
This converts the IRCAM data file called ircam_27aug89_1cl into a series of NDFs called rhooph1, rhooph2 etc. There is no format conversion applied.
ircam2ndf ircam_27aug89_1cl rhooph [32,34-36] fmtcnv
This converts four observations in the IRCAM data file called ircam_27aug89_1cl into NDFs called rhooph32, rhooph34, rhooph35, rhooph36. The scale and offset are applied.
ircam2ndf in=ircam_04nov90_1c config="KTC" obs=5 prefix=bias
This converts the fifth observation in the IRCAM data file called ircam_04nov90_1c.sdf into an NDF called bias5 containing the electronic pedestal in its data array. There is no format conversion applied.


The rules for the conversion of the various components are as follows:

IRCAM file


when Parameter CONFIG="STARE"


when Parameter CONFIG="CHOP"


when Parameter CONFIG="KTCSTARE"


when Parameter CONFIG="KTCCHOP"




If .OBS.TITLE is a blank string, OBS.DATA_OBJECT is copied to the NDF title instead.





IRCAM file

.GENERAL.INSTRUMENT.PLATE_SCALE becomes the increment between the axis centres, with co-ordinate (0.0,0.0) located at the image centre. The NDF axis units both become "arcseconds".





This excludes the components of OBS already listed above and DATA_BLANK.

Bad-pixel Handling

Elements of the data array equal to the IRCAM component .OBS.DATA_BLANK are replaced by the standard bad value.

Implementation Status: