When is the ideal time to light the Chanukah candles? The opinion of the GR”A is that one should light at shkia. In Yerushalayim, many hold of this opinion. The question that is asked is that at shkia it is still light outside. If so, the candles will not be noticed, thereby missing out on persumai nisa. Therefore, many poskim rule to light a few minutes after shkia. Rav Moshe Feinstein says to light 10 minutes after shkia. The idea is that when the sky starts darkening, the candles should then be lit.
The candles should be lit as long as there are still people walking outside who can see the candles. The Rama in siman 672 rules that even those that light indoors should preferably light at this time.

Mier Yeshiva Israel
By: Rabbi Tzvi Hyman