The Unnavigibility Of The Cloud Universe

Optical
The first Kirkasanter interstellar ships visited some of the many stars that are visible from Kirkasant. The crew of the Makt intended to take only the next step, steering by stars already charted on the edge of instrumental perception. However, that charting was imprecise because the absolute magnitudes, therefore the distances and relative positions, of the barely visible stars had not been determined as well as astronomers had believed: too much haze, shine and variability. Also, the Kirkasanters had not known how many stars there were only a few light-years beyond. Approaching wrongly identified stars, the Makt bypassed Kirkasant, eventually emerging from the Cloud Universe and plunging back into "...that forest of suns..." (p. 735) (For full reference, see here) three times without success.

Other
Although the light from supergiants is diffused and absorbed, their neutrinos might be detected and used as beacons. However, the effect is soon smothered because there are too many:

neutrino sources;
magnetic effects;
stars close together;
rapidly revolving double, triple and quadruple stars twisting the force lines;
radiations keeping much of the interstellar medium in a plasma state;
electromagnetic actions;
synchraton and betatron radiations;
nuclear collisions;
etc.

The noise level is too high for any extrapolable instruments because the laws of atomistics would not allow their filters to be precise enough.

Inertial navigation would work at kinetic velocities but on hyperdrive, which is necessary to cross parsecs, and because inertial and gravitational mass are identical, too rapid a change of gravitational potential can cause uncontrollable precession and nutation, which cannot be compensated for among so many closely packed stars moving on incalculably complex paths with too high a variation rate.

Although Jaccavrie can at any time follow a straight line into clear space, the significantly increasing cosmic radiation indicates not only magnetic acceleration but also enormous nova production which in turn implies hazards like neutron stars, rogue planets, large meteoroids and thick dust banks that might be undetectable before they are encountered.

Some stars excite pseudoquasar processes, detectable in the visible and short infrared wavelengths, in the interstellar medium although the radio bands are clear of that kind of wave.

Despite Jaccavrie's warnings and misgivings, Laure proceeds. Does Jaccavrie resent the time that he is spending with Graydal?