Talmud for Rosh Hashanah 47:6
השתא כולו אמרת לא חציו מבעיא אלא ה"ק חציו במים חציו ברקיע חציו בעבים חציו ברקיע חציו בעששית חציו ברקיע אין מעידין
Our Rabbis taught: '[If they say], We saw it in water, we saw it in a mirror, we saw it through the clouds, they are not allowed to testify concerning it. [If they say], We saw half of it in water, half of it through the clouds, half of it in a mirror, they are not allowed to testify concerning it'.
Jerusalem Talmud Rosh Hashanah
“To its North or its South?” There are Tannaim who state, “to its North” his words are accepted. There are Tannaim who state, “to its South” his words are accepted. He who said, “to its North” his words are accepted, from Ṭevet to Tamuz; he who said, “to its South” his words are accepted, from Tamuz to Ṭevet91The Babli 24a makes the changeover at the equinoxes, not the solstices. Ptolemy’s solar and lunar tables make such general statements unnecessary..
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