Q. Nice to talk with you, can you please let me know what is the earliest you can do Kiddush Levana. Thx.
A. On question 3279 regarding Kiddush Levana with a minyan after Tisha BAv ends, but before 72 (minutes after sunset, which is the opinion of Rabbenu Tam), when one is makpid (careful) to wait 72 for other things, we wrote: “Horav Shlomo Miller Shlit’a mentioned once that a minyan that davens early Maariv after the Shekia, could recite Kiddush Levana when in need, even only eighteen minutes after the Shekia, as long as they can clearly see then the moon.
The fact that one can recite Kiddush Levana with a group of people or a minyan and comply with the mitzva of ‘Berov Am Hadras Melech’ or keeping with a mitzva with many, and also avoiding some of forgetting to do it, is most important.”See also Teshuvos Vehanhogos (O.H. 4: 93).
Rabbi A. Bartfeld as revised by Horav Dovid Pam, Horav Aharon Miller and Horav Chanoch Ehrentreu Shlit’a