May one who is elderly and weak person go outside, see the moon, and then return indoors and be Mekadesh it from a siddur (recite the blessings), if it is too cold or one cannot carry there on Shabbos the siddur and there is also no window available?

Horav Shlomo Miller’s Shlit’a opinion is that if it would be possible to finish the brocho Toch K’dei Dibur or in the very short time of saying three words, he may, however that is practically impossible. Yet, he may dress properly for a very short while. He may also ask someone who carries or knows the brocho by heart to accompany him for that very short period.