Vishakha is the sixteenth, ruled by Jupiter, its symbol a triumphal archway (also a forked branch), its deity Indrāgnī — Indra and Agni as one, victory and fire together. The name means 'forked'.
Mechanically Jupiter is expansion and meaning, Indra is victory, Agni turns things into energy. Together: burning toward one goal. The fork is the key action of this segment — two branches ahead, choose one, and put the whole fire into it. The arch is what choosing rightly looks like; not choosing, or choosing and turning back, scatters the fire.
Where you'll recognise it: a strong sense of goal, long endurance for one thing, appetite for achievement, frightening focus, a certain emptiness after arriving, and a tendency to stall when you want both branches. Running well, you're the most persistent: once set, you go to the end, you finish long things, people want to push alongside you. Stuck, the goal eats you — the process lost to the getting, no next thing after arrival, or standing at the fork so long both sides go cold. Swati before it is the wind; Anuradha after it is companions: after a round of pushing you find that winning alone isn't as interesting.