The bracha on a rainbow is the subject of a disagreement on Brachos 59a. The Gemara brings זוכר הברית unattributed, Rabbi Yishmael the son of Rabbi Yochanan ben Beroka says נאמן בבריתו וקים במאמרו, and the Gemara concludes that you say both, זוכר הברית ונאמן בבריתו וקים במאמרו.
What happens if you see a rainbow during Musaf on Rosh Hashana? The bracha of zichronos also ends with זוכר הברית. On the other hand, the reference is to a different ברית. What is the best way to proceed?
- Zichronos does not cover the rainbow, so say the standard rainbow bracha after Shemoneh Esrei if it's still there.
- Zichronos does cover the rainbow.
(This is a very contrived case, and can only happen in a shul that's either running very late or faces west. I wouldn't be surprised if it's happened to someone at some point in history, but my primary purpose here is to understand the nature and potential interaction of these brachos.)