Hi Tom,

I am not an informatician, but I was wondering, if you could not just do the following:
- make a copy of the downloaded .tdf file,
- open the .tdf file with notepad,
- look - at the beginning of the file - at the lines of the 20 stars and how the data are arranged per line,
- take another G2V catalogue (--> google),
- re-arrange and shorten the data from this other catalogue in the same way, as they are in the (notepad =
tdf) file,
- copy the re-arranged data below the existing lines in the notepad / tdf file
-save the amaneded file as COLORCAL.tdf.

As I said, I am not an informatician (and I do not know for instance, whether you need also to change something in the lower part of the .tdf file (below the star list), perhaps because the number of the lines / stars has changed)?

But you could always give it a try (as you still have the backup copy).

Rudi