iraf.net

I am trying to create an image file from a text file. In my text file I have two columns; wavelength and flux, like the sample shown below. When I use RSPEC, it plots the correct flux but arbitrary wavelength scale, basically from 0 to 1000. I want it to use MY wavelength and NOT assign arbitrary wavelength. Please let me know how I should do this. Thanks!
1.24 1.1300
1.24 1.1200
1.24 1.1100
1.24 1.0600
1.24 0.9800
1.24 0.8830
1.24 0.8290
1.24 0.8280
1.24 0.8690

Set: "dtype=inter" in the parameter section; by default "dtype=linear" which ignores the wavelength values; in that case you should give "rspec" the wavelength of your first point and the step. But if your data is not equally spaced in wavelength that's trouble. "dtype=interp" makes a linear interpolation to your data so it might introduce some resampling and rounding errors but that's usually very small.