I’m trying to find sources for keeping 1 day of yom tov while Israel, instead of 2. I’ve discovered that this was the opinion of Rav Goren, the chief Rabbi of Israel, and that it is written in the sefer of Chacham Tzvi Hirsch Ashkenazi. I also have learned that it is followed by Chabad and is written in the Shulchan Aruch Harav. I’m trying to find any other sources that exist that support this opinion before I approach my Rabbi and ask him what to do. What can you tell me about this? Thank you, Moshe

The common practice and the Halacha as written in the Mishna Brurah is to keep two days unless you plan to stay. As for Chabad, they keep one day only of you are here for at least a year, similarly I don't know rav Goren to hold like the Chacham Tzvi. All the best