I thought I had it fixed!

I just now installed/re-installed a load of packages in order to build and run the ekosdebugger, which I have now done. 

See my post here  for what I did.

After launching kstars in ekosdebugger this time, I ran my 'test' again, and got up to 931 files before the crash (a record).

Could my installing dependency packages have stabilised my system?  Perhaps.

While the process was still up but non-responsive, I decided to do some investigating.  I ran:

lsof -p 17864 > ~/Documents/kstars_file_descriptors_on_crash.txt

17864 was the pid of kstars.

I'm attaching the output.  There were over 100,000 file descriptors in use at the time of the crash and most of them seem to be labelled as type=STREAM.  I wonder if it's something to do with trying to play an audio file on successful capture of an image and failing while leaving the FD open?