Since version 1.8.7 of PixInsight, which we are going to release in a few days, our reference platform is
Kubuntu 18.04 LTS. Our second reference platform is currently
FreeBSD 12. These are the only operating systems we use on all of our development workstations.
So far we have tested version 1.8.7 on the following Linux distributions:
Kubuntu 18.04 LTS
Kubuntu 19.04
Fedora 29
Fedora 30
Linux Mint 19.1
Any of the above distros are guaranteed to work nicely with PixInsight 1.8.7. My personal recommendation is Kubuntu. I
strongly recommend KDE Plasma as the best desktop environment for PixInsight, where our software is best integrated by far.