If a person who lives in Israel visits the United States for Yom Tob, with the intention of returning to Israel, how many days of Yom Tob must he observe? Does he observe one day, like Israeli residents, or two days, like a resident of Hutz La’aretz (the Diaspora)?
Maran, in his responsa, following the view of Rabbenu Zerahya Halevi (1125-1186), rules that although the visitor from Israel celebrates only one day of Yom Tob, he may not perform Melacha (activity forbidden on Shabbat or Yom Tob) on the second day. It goes without saying that he may not perform Melacha publicly, as the local residents who observe him might mistakenly conclude that Melacha is permissible on the second day of Yom Tob, and this would undermine their respect for the second day. However, according to this view, it is forbidden for the Israeli visitor to perform Melacha even in private. This is the view of many authorities, including the Peri Hadash (Rav Hizkiya Da Silva, 1659-1698) and the Hid"a (Rav Haim Yosef David Azulai, 1724-1806).
Hacham Ovadia Yosef follows this ruling, that an Israeli resident who visits the Diaspora must refrain from Melacha even in private on the second day of Yom Tob. However, he makes an exception with regard to the prohibitions of Mukseh, lighting matches, and turning on lights. There were authorities who allowed these activities on Yom Tob, and thus although we do not follow this view, an Israeli resident may rely on this ruling when visiting the Diaspora on the second day of Yom Tob, and perform these activities in private. Besides these exceptions, however, he must refrain from Melacha on the second day of Yom Tob, even in private.
How should a person pray in such a case?
There is a famous responsum by the Peri Hadash in which he describes how he conducted himself when he confronted this very situation. The Peri Hadash lived in Eretz Yisrael, but once spent Yom Tob in Egypt. He writes that he put on his Tefillin in private, and recited Shema while wearing Tefillin. He then removed his Tefillin and went to the synagogue to pray Shaharit. He recited the Amida together with the congregation, though he, of course, recited the weekday Amida, while the congregation recited the Amida for Yom Tob. (Interestingly, he writes that he began the Amida slightly before the congregation began the Amida, because the weekday Amida is lengthier than the Amida for Yom Tob.)
Hacham Ovadia Yosef follows this ruling of the Peri Hadash, that a person in this situation should wear Tefillin in private, recite Shema, and then remove his Tefillin and pray with the congregation, even though he recites a different Amida. Regarding Hallel, Hacham Ovadia writes that a visitor from Israel may recite Hallel with the congregation on the second day of Yom Tob, though obviously he does not recite a Beracha over the recitation. Furthermore, Hacham Ovadia adds, he should preferably recite Hallel "Be’dilug," meaning, omitting the sections that are omitted on Rosh Hodesh. Some authorities maintain that it is improper to recite the complete Hallel on occasions when it is not Halachically mandated, and therefore, in deference to this view, a person in this situation should make a point to recite the abbreviated Hallel of Rosh Hodesh, rather than the complete Hallel.
Summary: An Israeli resident who visits the Diaspora, and plans to return to Israel, must refrain from Melacha on the second day of Yom Tob even though he does not observe that day as a Yom Tob. In private, he may light a match, turn on lights and handle Mukseh, but all other restrictions of Yom Tob must be observed even in private. He should wear Tefillin in private and recite Shema while wearing them, after which he should remove the Tefillin and go to the synagogue and pray with the congregation. He recites the weekday Amida while they recite the Amida for Yom Tob. He may recite Hallel with the congregation, though without reciting a Beracha, and, preferably, he should recite the abbreviated Hallel which we recite on Rosh Hodesh.
