In a recent answer you said that saying tehillim at night is fine and in fact that it is a mitzvah. I have heard otherwise - that it is not kadai to say tehillim after the stars are visible. Please could you clarify this for me? Also, please may I have the sources for both positions? Thanks

The Ben Ish Chai writes (First year, Parashat Pekudei, 7) that Tehilim can be said at night - after midnight. Torah study can be done but reading Psukim should not be done before Chatzot (midnight) unless one read the interpretation or explanation. On Thursday, Friday and Yom Tov nights this is irrelevant and one may study and say Tehilim all night. Rabbi Ro'i Margalit