[Avodah] Yoma Arichta - RH in EY

[Marty Bluke]

R' Wolpoe asked:
<What is the earliest source for observing two days of RH even in EY?

The Baal Hamaor in Beitzah (6a) as well as the Rosh there,  quotes
that R' Nissim Gaon asked R' Hai Gaon whether 1 or 2 days should be
kept in EY. R' Hai answered 1 day.

R' Zevin in Moadim B'Halacha has a long piece where he explains that
there were 4 periods regarding RH (ayen sham).

I don't think that there is an earlier source for this, the machlokes
whether to keep 1 or 2 days is based on the following.

They made a takana ((Mishna RH 30a) that they would not accept eidim
after mincha and in that situation they would finish out the day as
Yom Tov (even though it was for sure not going to be Yom Tov that
day). That takana continued in some form even after the Curban Habayis
(see Beitzah 5b machlokes Rashi and Tosafos). Based on this takana,
the Gemara says that the 2 days of RH are 1 kedusha.

If you lived in Yerushalayim when teh Beis Hamikdash was still
standing if teh edim came on the first day RH was only 1 day. The same
applied to the period after the churban when they were still mekadesh
al pi har'iya. People who lived in teh Beis Havaad where they were
mekadesh the chodesh only had to keep 1 day if the edim came on the
first day.

Based on this the Baal Hamaor makes the following argument (which
seems to be what the Geonim held). He says that since kiddush
hachodesh could have been done anywhere in EY, all of EY has the
status of Beis Havaad and therefore never had a minhag of keeping 2
days and therefore only 1 day is observed.