A Moment Of Realization On Vanessa

"A Sun Invisible."

I itemized Falkayn's detective work:

Science Fiction And Detective Fiction

How Falkayn Did It

- but seem to have missed his Andersonian moment of realization. He lists the clues regarding the location of the enemy sun:

the Neuheimer and Vanessan constellations are recognizably similar;
the two systems were parts of an interstellar empire built at sub-light speeds;
the Neuheimer sun, Antoran, must be large, bright and energetic;
it has six planets in its liquid-water zone with eccentric orbits.

"Unheard of. You'd almost think that -
"Falkayn sat bolt upright. His pipe dropped from his jaws to his lap. 'Holy...hyper...Judas,' he gasped.
"Thereafter he thought most furiously. He did not come back to himself until the coals from his pipe set fire to his trousers." (IV, p. 295)

If that is not a typical Andersonian moment of realization, then I don't know what it is.