a short example of FITS Table HDU read access using RubyFits

conver_fits_to_csv.rb

#!/usr/bin/ruby

# This script dumps data contained in a FITS Table HDU into a CSV file using RubyFits.
# Usage: 
# ruby conver_fits_to_csv.rb FITS_FILE
# Output:
# - Header: FITS_FILE_n_header_HDU_NAME
# - Data  : FITS_FILE_n_data_HDU_NAME
# (n is HDU index)

require "RubyFits"
inputFileName=ARGV[0]
fits=Fits::FitsFile.new(inputFileName)
puts "There are #{fits.hdus.length} HDUs (including Primary HDU)."

#process all HDU except for Primary HDU
for i in 1...(fits.hdus.length)
        hdu=fits.hdu(i)
        hduName=hdu.getHDUName()
        puts "Processing HDU[#{i}] = #{hduName}"

        #dump header
        outputFileNameHeader=inputFileName+"_#{i}_header_#{hduName}"
        puts " Output file (header) = #{outputFileNameHeader}"
        outputFileHeader = open(outputFileNameHeader,"w")
        hdu.getHeaders().each(){|entry|
                outputFileHeader.puts "#{"%-10s"%entry.keyword} = #{"%-30s"%entry.svalue} / #{entry.comment}"
        }
        
        #dump table data
        outputFileNameData=inputFileName+"_#{i}_data_"+hduName
        puts " Output file (data) = #{outputFileNameData}"
        outputFileData = open(outputFileNameData,"w")
        hdu.each_row(){|row|
                outputFileData.puts row.join(",")
        }
end