Second Day of Yom Tov
Outside of Israel we keep a second day of Yom Tov and even though originally when it was established it was because we weren’t sure about the dates, and nowadays we have an established calendar, the obligation still exists. This is because the rabbis decided that maybe one of the governments ruling over us outside of Israel can decree that we can’t learn torah, and we would get confused with how to set when Rosh Chodesh is and mistakenly eat chametz on Pesach. 
- Most poskim hold that one must light the candles for the second day of Yom Tov after nightfall because it is forbidden to prepare from one day of Yom Tov for the next.
- Some say that if is going to say Kiddush for the second day of Yom Tov early before nightfall, one is permitted and should light the candles before Kiddush so that one can see the candles during Kiddush. 
- Everything that is prohibited on the first day is equally forbidden on the second except to for a sick person who is not in danger of dying. On the first day you can only get healed by a non-Jew but on the second day a Jew can do himself as long as its only violating a rabbinic prohibition but something that is forbidden from the Torah is forbidden even on the second day. 
- One other case that is different is with regards to burying a dead body which on Yom Tov rishon would only be done by a non-Jew but on the second day it would be allowed for a Jew to perform himself. 
- However, the two days of Rosh Hashana are considered one long day of Yom Tov and therefore there is not even that difference. 
Halachot of an Israeli outside of Israel
- An Israeli who leaves Israel and plans on returning, is forbidden from doing melacha. 
- Some say that this is only melacha in public  while most say that this includes even doing melacha in private 
- There is what to rely on for an Isreali who is outside Israel on the second day of Yom Tov in private to carry muktzeh on Yom Tov, light a match, or turn on a light. 
- If the first day of Yom Tov falls out on Shabbat an Israeli may light a candle for Havdalah. 
- If Yom tov sheni falls out on a Friday he doesn’t have to do an Eruv Tavshilin because when people see him cooking on Friday for Shabbat they don’t know whether or not he did an Eruv Tavshilin. 
- If he owns a factory outside of Israel that is run by non-jews he is allowed to let them work on the second day since it is technically a weekday for him. 
- With regards to prayers, if it’s the second day of Shavuot, or the eighth day of pesach, or 9th of succot he should put tefillin on at home, say Kriat Shema, and then go to shul to pray with them. He should pray the weekday prayer or if it’s the second day of pesach or succot then chol hamoed because nobody can tell which shmoneh esrei he’s saying. 
- When they say hallel he should say it along with them without a beracha and by skipping the paragraphs one does on Rosh Chodesh, and when they say Mussaf, if its chol hamoed for him he says Mussaf but say “et yom mikra kodesh” instead of “et Yom Tov mikra kodesh”, and if it’s a regular weekday he should just say a few chapters of tehillim and pretend to say the shmoneh esrei. 
- It is forbidden for Israelis outside of Israel to organize a minyan for weekday, however, if the second day of Yom Tov is Shabbat it’s permissible for Israelis to form a minyan but the Shaliach Tzibbur shouldn’t raise his voice so that it’s heard outside. 
- If an Israeli is outside Israel for the second day of Yom Tov he can't say Kiddush for someone who is observing two days of Yom Tov. 
- If an Israeli is outside Israel for the second day of Yom Tov he should not receive an Aliyah. If he is the only Kohen in the minyan, a Levi or Yisrael should be called up in his place and it's preferable for the Kohen to leave the shul. If he's not the only Kohen, then a different Kohen should be called up. Some say that after the fact if he was called up he should take the Aliyah.
Seder on Pesach
- An Israeli who is outside of Israel for Pesach must participate fully in a second seder, even if he is around people who know he is Israeli.
Halachot of a Jew from Diaspora in Israel
- However, it is permissible for non-Israelis to make a minyan for Yom Tov sheni in Israel because that is already an established custom. 
Asking an Israeli do Melacha on Yom Tov Sheni
- A non-Israeli who is in Israel has what to rely on ask an Israeli to do melacha for him on Yom Tov Sheni. 
Who should keep two days
- A non-Israeli who is in Israel for Yom Tov should keep two days of Yom Tov. 
- Someone who is making Aliyah to Israel on condition that everything works out and hasn't yet decided to stay according to some poskim should keep only one day, while according to many others should still keep two days. 
- A Sephardic unmarried Yeshiva student should observe only one day of Yom Tov because he doesn’t have an established in either place and we therefore hope that he will find a good wife and job and be able to remain in Israel. 
- According to some poskim, if one generally visits Israel for all Shalosh regalim, he only keeps one day of Yom Tov. 
"One and a Half Days"
- There is a third possibility sometimes referred to as one and a half days. This doesn't mean to refrain from doing melacha for half of the day but rather to keep the stringencies of those keeping one day and those keeping two. This means not doing any melacha on the second day of Yom Tov, but wearing tefillin with a beracha. (Second day of shavuot, eight day of pesach, and ninth day of sukkot, or for those who wear tefillin on chol hamoed also second days of pesach and sukkot) 
- (Beitza 4b)
- The son of the Prisha (Introduction to Prisha YD) quotes his mother as saying that on the second day of Yom Tov one must light after nightfall so as not to prepare from one day of Yom Tov for the next. The Levush 488 and Eliyah Rabba 488:7 argues that one may light before nightfall as long as it is getting dark out because the candles are beneficial even for the first day so that one can see better in the light. Mishna Brurah 514:33 agrees. Nitai Gavriel (Yom Tov v. 2, 15:3, p. 107) points out that the Eliyah Rabba would agree with the Prisha's mother in the common case where there are electric lights no and the candles doesn't make it easier to see.
- Rav Poalim 4:23 and Ben Ish Chai (Bamidbar #2) writes that since one should see the candles while saying Kiddush, and some even say that this is absolutely necessary, lighting the candles is an immediate need and not an issue of preparing from one day of Yom Tov for the next. He goes on to explain that the dispute between the Prisha's mother and Eliyah Rabba one applies is one is lighting before nightfall and making Kiddush after nightfall.
- S”A and Rama 496:2
- S”A 496:1-2
- S”A 496:1-2
- S”A 468:3
- Sh”t Avkat Rochel (Rav Yosef Karo; Siman 26), Sh”t Mabit 3:149, Taz 496:3
- Tosfot Pesachim 52a s.v. BeYishuv, Sh”t Radvaz 4:73, 4:258, Sh”t Maharashdam 15, Sh”t Mishpat Tzedek 2:49, Magen Avraham 496:4, Birkei Yosef 496:3, Mishna Brurah 496:9, Chazon Ovadyah (Yom Tov pg 111)
- Sh"t Igrot Moshe OC 4:105 permits turning on or off a light in private since when people see the light turn on and off they think it’s on an automatic clock. Chazon Ovadyah (Yom Tov pg 111-2) writes that even though one should be strict in general, one can be lenient regarding Muktzeh, lighting matches, and turning on a light because there is a dispute whether such is permissible on Yom Tov in general. Sh”t Shevet HaLevi 7:65 writes the same logic regarding Muktzeh.
- Sh”t Shevet HaLevi 7:65
- Mishna Brurah 496:13
- Chazon Ovadia page 130, Shmirat Shabbat Kihilchata 31:80
- Mishna Brurah 496:13, Chazon Ovadyah (Hilchot Yom Tov pg 112), Sh"t Yechave Daat 3:35
- Chazon Ovadia (Hilchot Yom Tov page 111-4)
- Chazon Ovadia (Hilchot Yom Tov page 115), Yom Tov Kihilchato (page 67)
- Rav Shlomo Amar on yutorah.org (about min 25) in a shiur on Arievut given at Yeshiva University
- Kitzur Shulchan Aruch 23:16
- Rav Mordechai's comments on Kitzur Shulchan Aruch 23:9
- Sh"t Iggerot Moshe OC 5:24:3
- Sh"t Avkat Rochel 26, Yom Tov Kihilchato (page 67)
- Yalkut Yosef (Kitzur S”A 496:27; Chazon Ovadyah (Yom Tov pg 138)) permits a non-Israeli to ask an Israeli to do melacha for him on Yom Tov Sheni. However, Sh”t Igrot Moshe 3:73 and Sh"t Shema Shlomo 1:9 forbid. Rav Elyashiv (in Kuntres Teshuvot siman 54) writes that the only concern is Memotzi Chefsecha which is permissible for a dvar mitzvah.
- Mishna Brurah 496:13, Chazon Ovadyah (Yom Tov pg 133), Rabbi Mansour on dailyhalacha.com. This is disagreement with the opinion of the Chacham Tzvi (responsa 167) who holds that a non-Israeli who is in Israel for Yom Tov keeps one day.
- Rav Elyashiv (quoted by Yom Tov Sheni KeHilchato pg 81) holds that one should keep one day, while Rav Moshe Feinstein (quoted by Yom Tov Sheni KeHilchata) and Chazon Ovadyah (Yom Tov pg 130) hold that one should keep two days (this is summarized on http://www.dailyhalacha.com/Display.asp?ClipID=2118)
- Chazon Ovadia (Rav Ovadyah Yosef) page 130, Sh"t Yabea Omer 6:40, Sh"t Yechave Daat 1:26
- Sh"t Minchat Shlomo 1:19(7), Chazon Ovadyah (pg 152), http://dailyhalacha.com/Display.asp?ClipDate=4/15/2011. Chacham Benzion Abba Shaul (Or Litzion 3: pg. 225 disagrees and says they should still observe two days of Yom Tov
- Nefesh Harav 84-85. This is the opinion of Rav Chaim Soloveitchik quoted in Mesorah torah journal (http://www.ou.org/pdf/mesorah/mes%206.pdf) volume 6 page 18.