Description:
This application
converts an Asterix data cube into a standard
NDF. See Section
"Notes
" (below) for details of the
conversion.
Usage:
ast2ndf in out
Parameters:
IN = NDF (Read)
The name of the input Asterix
data cube. The file extension (.sdf) should not be included since it is appended automatically by the
application.
OUT = NDF (Write)
The name of the output NDF containing the data cube written
by the application. The file extension (.sdf) should not be included since it is appended
automatically by the application.
Examples:
ast2ndf ast_cube ndf_cube
This example
generates NDF data cube ndf_cube (in file ndf_cube.sdf) from Asterix cube ast_cube (in file
ast_cube.sdf). Notes:
This application accepts data in the format used by the Asterix
package (see
SUN/98). These data are cubes, with two axes comprising a regular grid of
positions on the sky and the third corresponding to energy or wavelength. The data are
Starlink
HDS files which are very similar in format to a standard NDF. The following points
apply.
-
The Asterix QUALITY array is non-standard. There is no QUALITY component in the output NDF.
Instead ‘bad’ or ‘null’ values are used to indicate missing or suspect values.
-
The VARIANCE component is copied if it is present.
-
The non-standard Asterix axis components are replaced with standard ones.
-
The order of the axes is rearranged.
References
-
-
D.J. Allan and R.J. Vallance, 1995, in SUN/98: ASTERIX – X-ray Data Processing System,
Starlink.
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Copyright © 2015 Science and Technology Research Council