It would be really useful to have the "name" of the optical train in the FITS metadata.

At the moment in the metadata the fields that come out of ekos I can see (exiftool) appear to be :
Instrument : The camera / sensor name
Telescope : The mount driver name
Focallen : focal length from the optical train (lens / telescope modified by the barlow factor)
Aptdia : aperture from the optical train

I currently use a Canon 400 F5.6 prime lens and an Orion 8" reflector with an 800mm focal length. I also use a 1.4 extender and a 2.0 extender.

For the various combinations I use, I have setup 5 optical trains. It would make things much easier when searching through metadata if the optical train name was in the metadata as well.

Good idea, but this requires INDI to provide a method to add arbitrary headers. Maybe something I'll work on for INDI 2.0.0