Ardazir

When Dominic Flandry escaped from the Ardazirho (see here), he brought with him a copy of their navigator's manual, which should reveal crucial military intelligence, the coordinates of the enemy's planetary system. This is comparable to the occasion when he captured a spaceship of the McCormac rebels and thus acquired their codes, ending the rebellion at a single stroke.

Meanwhile, he makes deductions about Ardazir:

warmer than Terra, though not excessively;

its hot star, emitting strongly in the ultraviolet wavelengths, splits water molecules and sends hydrogen atoms into space;

the ozone layer gives insufficient protection to the hydrosphere;

a dry planetary surface with seas but not oceans;

surface gravity about 1.5, retaining a terrestroid atmosphere;

the Urdahu conquered other cultures very recently;

their discordant uniforms reflect local parochialisms;

Flandry knows how to split such an empire, as he did on Scotia.