spacer link to MAST page spacer logo image spacer
link to STScI page

Converting FITS Coadded Scan files to text using FTOOLS

We start FTOOLS as usual. As before, the stacked data consists of primary array header, a binary table extension header, and 1 row of 6 columns of binary table data, so we read in a header, an extension header, and the 6 columns of the extension.

Let us say we are interested in the OI 988Å multiplet towards the star Lambda Sco. Using the U1 archive search we find there is a stack of scans of this line stored in the file c001-074.bu1. The FTOOLS command we want to use is fdump, but the default output format of this command is to list the contents of the different columns sequentially (ie. all of the wavelength information, then all of the fluxes, etc) while one usually wants to have the wavelength, net flux, etc on a single line. So what we do is set some of the flags to get a multi-column ascii table without header, column name, or row number information as the output using the command pset:

	>pset fdump
	Name of FITS file and [ext#] ():  
	Name of optional output file (STDOUT):  
	Names of columns ():  
	Lists of rows (-):  
	Define a new field separator (default is space) ():  
	Page width (80):  132
	Print header keywords? (yes):  no
	Print data? (yes):  
	Print column names? (yes):  no
	Print column units? (yes):  no
	Print row numbers? (yes):  no
	Show scaled values? (yes):  
	Align columns with names? (yes):  
	Print every nth row (1):  
	Use TDISPn keywords? (no):  
	Display entire row at once? (no):  
	Page through output to terminal (yes):  
	Overwrite output file if exists? (no):  
	Be case sensitive about column names? (no):  
	More? (yes):  
	mode (ql):

We can now use the fdump command to create the ascii file, if we (for example) want to create an ascii file for the OI 988Å data for Lambda Sco we would type:

	Name of FITS file and [ext#][] c001-074.bu1
	Name of optional output file[STDOUT] c001-074.txt
	Names of columns[] -
	Lists of rows[-]

We then have an ascii file with the six columns of data that we can read into other plotting or analysis programs.

Example provided by jtl