אמר רבי אלכסנדרי אמר רבי יהושע בן לוי הרואה את הקשת בענן צריך שיפול על פניו שנאמר כמראה הקשת אשר יהיה בענן וגו׳ ואראה ואפל על פני לייטי עלה במערבא משום דמחזי כמאן דסגיד לקשתא אבל ברוכי ודאי מברך
Rabbi Alexandri said that Rabbi Yehoshua ben Levi said: One who sees a rainbow in a cloud must fall upon his face, as it is stated: “As the appearance of the bow that is in the cloud in the day of rain, so was the appearance of the brightness round about. This was the appearance of the likeness of the glory of the Lord. And when I saw it, I fell upon my face” (Ezekiel 1:28). Yet, in the West, Eretz Yisrael, they would curse one who fell upon his face when seeing a rainbow because it appears as one who is bowing to the rainbow. As far as blessing is concerned, however, all agree that one certainly recites a blessing.
What if a Minyan is meeting outside (or facing large windows) and a rainbow appears opposite them? Should they face the wrong direction? Proceed as usual? Delay?
Does it matter which prayer they are gathered to pray? Delaying Mincha could mean missing it entirely, delaying Shacharit could mean missing its ideal time, and delaying Arvit would probably be a good thing anyway. What if delaying will break up the Minyan?
Do any sources address this case and invoke the above cited curse? Does bowing without falling on one's face not qualify?